The pool dimensions that will minimize the cost of construction are length of square bottom = 20 ft and height of pool = 5 ft
Let l be the length of side of the square bottom of the pool and h be the height of the pool.
Its volume V = l²h
Now, the total surface area of the pool equal the area of its sides plus the area of its base.
The area of its 4 sides is 4lh.
Since the cost of the side of the pool is $80 per square foot, the total cost for the sides of the pool is C = $80 × 4lh = $ 320lh
Also, The area of its square bottom is l².
Since the cost of the side of the pool is $40 per square foot, the total cost for the square bottom of the pool is C' = $40 × l² = $ 40l²
So, the total cost of the pool is C" = C + C' = 320lh + 40l²
C" = 320lh + 40l²
Since the volume equals 2000 ft³, V = l²h
2000 = l²h
h = 2000/l²
Substituting h into C", we have
C" = 320lh + 40l²
C" = 320l × 2000/l² + 40l²
C" = 640000/l + 40l²
To find the value of l which makes C" minimum, we differentiate C" with respect to l and equate it to zero.
So, dC"/dl = d(640000/l + 40l²)/dl
dC"/dl = d(640000/l)/dl + d(40l²)/dl
dC"/dl = -640000/l² + 80l
Equating dC"/dl to zero, we have
-640000/l² + 80l = 0
-640000/l² = -80l
Cross-multiplying, we have
640000 = 80l³
Dividing through by 80, we have
l³ = 640000/80
l³ = 8000
Taking cube root of both sides, we have
l = ∛8000
l = 20 ft
We differentiate C" twice to determine if this value of l gives a minimum for C".
So, d²C"/dl² = d(-640000/l² + 80l)/dl
d²C"/dl² = d(-640000/l²)/dl + d(80l)/dl
d²C"/dl² = 640000/l³ + 80
Substituting l = 20, we have
d²C"/dl² = 640000/l³ + 80
d²C"/dl² = 640000/20³ + 80
d²C"/dl² = 640000/8000 + 80
d²C"/dl² = 80 + 80
d²C"/dl² = 160 > 0
Since d²C"/dl² = 160 > 0. So, l = 20 ft gives a minimum for C".
Since h = 2000/l²
Substituting l = 20 into the equation, we have
h = 2000/l²
h = 2000/20²
h = 2000/400
h = 5 ft
So, the pool dimensions that will minimize the cost of construction are length of square bottom = 20 ft and height of pool = 5 ft
Learn more about dimensions of a pool here:
https://brainly.com/question/22112169
The length and breadth of a rectangle are (2x + 1) cm
and (x + 3) cm, respectively. If the area of the
rectangle is 88 cm^2 ,find:
a. the value of x
b. the perimeter of the rectangle.
Answer:
Step-by-step explanation:
Area = 88 sq.cm
length * width = 88
(2x + 1)(x + 3) = 88
2x*(x +3) + 1*(x + 3) = 88
2x*x + 2x*3 + x + 3= 88
2x² + 6x + x + 3 = 88
2x² + 7x + 3 - 88 = 0
2x² + 7x - 85 = 0
2x² - 10x + 17x - 85 = 0
2x(x - 5) + 17(x - 5) =0
(x - 5)(2x + 17 )= 0
x - 5 = 0 {Ignore 2x +17 = 0 as it gives a negative value}
x = 5
b) length = 2x + 1 = 2*5 + 1 = 10 +1 = 11 cm
breadth = x+ 3 = 5 + 3 = 8 cm
Perimeter = 2*(length +breadth}
= 2* (11 + 8)
= 2 * 19
= 38 cm
Compared to last year, the population has increased 25%. The population is now 6,600. What was the population last year?
What number of population do I put for each for percentage?
Answer:
4,950
Step-by-step explanation:
:)
1,650-25% 3,300-50% 4,950-75% 5,280-100%
Step-by-step explanation:
convert the percentage to a decimal then multiply by 6,600. To get the number of people of 100%, divide 1.25 (the percent of 6,600) by 6,600. That should be right,
HELP ME I GOT 67 POINTS THAT I WILL GIVE AND ILL GIVE YOU BRAINIST
Answer:
35.325 in³
Step-by-step explanation:
Since the base of a cylinder is a circle,
area of cylinder= πr²h
Radius, r
= diameter ÷2
= 3 ÷2
= 1.5 inches
Volume of can
= 3.14(1.5)²(5)
= 35.325 in³
Pleaseee helpppp me!!!!!!!!!!!!!
Answer:
The graph is linear and increasing from x = -6 to x = -2.
The graph is nonlinear and decreasing from x = -2 to x = 0.
Step-by-step explanation:
Linear means it has a constant slope, or a constant rate of change. That makes a straight line on a graph. On the given graph, you can see the straight line increasing from x = -6 to x = -2.
Non-linear is just anything that isn't a constant slope, and makes a curve on a graph. On the given graph, the curve decreases from x = -2 until x = 0, where it reaches its lowest point and starts heading upwards again.
The coordinates of which point are (–3, –6)?point Apoint Bpoint Cpoint D
The coordinates of which point are (–3, –6) is point B
What are coordinates?Coordinates are the position of a point in the coordinate plane.
From the graph, we have the following highlights
Point B is at x = -3, and y = -6
The above means that:
(x,y) = (-3,-6)
Hence, the coordinate of (-3,-6) is point B
Read more about coordinates at:
https://brainly.com/question/17206319
Answer:
its point b edge 2022
Step-by-step explanation:
Is that the right answe plzzz help me
Answer:
Your answer is All of the Above.
Hope this helps!
Step-by-step explanation:
OA is the radius
OC is the radius
and OB is the radius
( They are all half length of the circle )
Solve the equation-10 +1 +7x =37
Answer:
Answer in Explanation
Step-by-step explanation:
-10 + 1 + 7x = 37
-9 + 7x = 37
Add 9 on both sides to leave 7x alone
7x = 46
Divide by 7 to leave x alone
x = 46/7 or 6.57
If the equation is positive 10 at the beginning instead of -10 then this is the answer for that:
10 + 1 + 7x = 37
11 + 7x = 37
Subtract 11 from both sides to leave 7x alone
7x = 26
Divide by 7 to leave x alone
x = 26/7 or 3.7
how to work out 85% of a number
Answer:
you change the percent into a decimal and multiply because of means multiply
Step-by-step explanation:
lets say you finding 85% of 4
.85 x 4
5
Find the arc length of the semicircle.
Elther enter an exact answer in terms of or use 3.14 for and enter your answer as a decimal,
units
Answer:
area is 39.27
Step-by-step explanation:
help me please!!!!!! 20 points!
Answer:
Step-by-step explanation:
2x = x + 40
2x - x = x - x + 40
x = 40
∠I = ∠Q = 33°
∠H = ∠P = 80°
∠J = ∠R = 67°
5x - 14 = 3(3x + 6) + 5
Answer:
x= -9.25
Step-by-step explanation:
5x - 14 = 3(3x + 6) + 5
5x - 14 = 9x + 18 + 5.......distribute
-4x = 37.............move values and combine like terms
x= -9.25.............divide both sides by -4
a%b when a=2 and b=1/2
Answer:
0.01
Step-by-step explanation:
If two figures are similar, what can you say about them? Be specific and give at least 3 details.
Answer:
im confused as to if these terms are supposed to be specific or if you are looking for certain ones
Step-by-step explanation:
but i would say congruent, corresponding angles, and equal
!!Help!!
solve for x
WXY = XYW ( = 41 ) ⇒ XYW is a isosceles triangle
⇒ XW = YW
⇒ 54 = 6x + 6
⇒ 6( x + 1 ) = 54
⇒ x + 1 = 9
⇒ x = 8
ok done. Thank to me :>
!!!WILL MARK BRAINLIEST IF ALL ARE ANWSERED!!! please provide short explanations
Answer:
20= 20
21. 10
22. 1.8
23. 4.4
24. 32
25. 7/9
If a=6, b=12,and c=4, then what does 2ab-c^2 equal?
Answer: 2(6)(12)-4^2 = 128
What is the prime factorization of 100,000?
Answer: 2^5× 5^5
Solve for x. 5.8 = 4x+0.2
Answer: x= 1.4
Find the area of this shape.
Answer: Area = 1.21
What is the lateral surface area of this rectangular prism?
Answer: 208 in^2
5/9 + 1/3 × 1/3 = 0.66666666666 = 2/3
Step-by-step explanation:
The prime factorization of 100,000 is 2^5 × 5^5. Since it has a total of 10 prime factors, 100,000 is a composite number.
-----------------------------------------------------------------------------------------------------
5.8-0.2=4+0.2−0.2
5.6 = 4x
5.6/4 = 4x/4
x= 1.4
-----------------------------------------------------------------------------------------------------
Square sides are equal..
A=a^2=1.1^2≈1.21
-----------------------------------------------------------------------------------------------------
The lateral surface area of a rectangular prism can be calculated by finding the sum of all the lateral faces of the prism, i.e. the total area excluding the area of the bases. The formula to find the surface area of a rectangular prism is given as, Lateral surface area of a rectangular prism = 2(l + b) h square units.
When a prism has its bases facing up and down, the lateral area is the area of the vertical faces. (For a rectangular prism, any pair of opposite faces can be bases.) The lateral area of a right prism can be calculated by multiplying the perimeter of the base by the height of the prism.
-----------------------------------------------------------------------------------------------------
Choose the steeper line.
y=-6x+1
or
y=-3x-2
Answer: y=-3x-2
Step-by-step explanation:
Slope is rise over run. The slope of y=-3x-2 is -3, which is 1 down/up and 3 to the right/left. The slope of y=-6x+1 is -6 which is 1 down/ up and 6 to the right/left. When the graph is going 3 steps to the right/left, it is steeper than when its going 6 steps to the right/left.
Find the value of x in each case
Answer:
Step-by-step explanation:
∠AEB + ∠FEC = 180 {linear pair}
∠AEB = 180 - 4x
DE // AB , AE is transversal,
∠EAB = ∠DEA {Alternate interior angles}
∠EAB = 2x
∠EBC = ∠AEB + ∠EAB {Exterior angle property}
6x = 180 - 4x + 2x
6x = 180 - 2x
Add 2x to both sides
6x + 2x = 180
8x = 180
x = 180/8
x = 22.5
In the figure, lines j and k intersect to form the
angles shown. What is the measurements of angle 1
What are the x and y -intercepts for the equation 5x - 4y = 10
Answer:
x=2
y= -2.5
Step-by-step explanation:
x int
1.) set y to 0 (5x -4(0)=10
solve for 5x=10
y int
1.) set x to 0
solve for -4y=10
Answer:
x=2, y=-5/2
Step-by-step explanation:
to find the 'x' intercept, set the 'y' value to zero and solve:
5x - 4(0) = 10
5x = 10
x = 2
to find the 'y' intercept, set the 'x' value to zero and solve:
x(0) - 4y = 10
-4y = 10
y = -10/4 or -5/2
answer this question!.
Answer:
∠A = 44°
Step-by-step explanation:
Let b represent the measure of the exterior angle at B. Let c represent the measure of the exterior angle at C. The sum of angles in the lower triangle is ...
b/2 +c/2 +68° = 180°
b +c = 360° -136° . . . . . multiply by 2, subtract 136°
b +c = 224°
__
The exterior angle b is the supplement of the interior angle there, so the interior angle B is ...
B = 180° -b
The exterior angle c is the sum of the remote interior angles, so we have ...
c = B +A
c = (180° -b) +A
A = (b +c) -180° . . . . . . . . add b-180° to both sides
A = 224° -180° = 44° . . . . substitute for (b+c)
The measure of angle A is 44°.
_____
Additional comment
The angle naming is perhaps a little unconventional, but we wanted to use names that made the answer less cumbersome to write. We consider the angle A, B, C to be the interior angles of ΔABC, and we have named the exterior angles at B and C as 'b' and 'c'.
Conventionally, 'b' and 'c' would name the sides opposite angles B and C, respectively. We're not concerned with side lengths here, so we used those letters for an unconventional purpose.
The base of the following pyramid is a square. If the volume of
the pyramid is 360 feet^3, what is the missing length? Round the
answer to the nearest hundredth.
Answer:
h = 12.52 ft
Step-by-step explanation:
volume of pyramid is 1/3*b*l. b is the base and l is the height we know that this equals 360 because it is given in the text. we also know b=8^2 since the base is a square so b=64. divide 360 by 1/3*64*pi to get l, l=5.3715. next we will use the pythagorean theorem to find h. first find the diagonal of the base: 8sqrt(2), now using the pythagorean theorem, we have h^2=5.3715^2 + (8sqrt(2))^2= 28.8528+128=156.8528. square root to get12.5241
Solve the proportion for v.
6
0]>
9 =
100
V
v = [?]
Answer:
v = 12
Step-by-step explanation:
[tex]\frac{9}{v}[/tex] = [tex]\frac{6}{8}[/tex] ( cross- multiply )
6v = 8 × 9 = 72 ( divide both sides by 6 )
v = 12
Answer:
v=12
9/v =6/8 (cross - multiply)
6v = 8 x 9 = 72 (divide both sides by 6)
v = 12
Step-by-step explanation:
that's my answer
Barbara wants to buy muffins. Which is the best deal? O a. 9 muffins for $7.92 O b. 4 muffins for $3.60 O c. 6 muffins for $5.34 O d. 8 muffins for $7.60 N
Answer:
D
Step-by-step explanation:
Hope it can help you lovelots
#LEARN WITH BRAINLY
find the measure of angle 1 and angle 2. justify your answer
Answer:
∠ 1 = 95° , ∠ 2 = 130°
Step-by-step explanation:
∠ 1 = 95° ( alternate angles )
∠ 2 and 50° are same- side interior angles and sum to 180°
∠ 2 + 50° = 180° ( subtract 50° from both sides )
∠ 2 = 130° ( same- side interior angle )
The formula for the area of a rhombus with diagonals of lengths c and d is A= 1/2 cd.
a. Solve the formula for c.
b. The area of a rhombus is 35 square feet. The length of one of the diagonals is 10 feet. What is the length of the other diagonal?
c. In a square (which is a rhombus), the lengths of the diagonals are the same. If a square has an area of 32 square feet, then what is the length of each diagonal
Answer:
I think it's A
Step-by-step explanation:
i apologize if I'm wrong
how many years in two scores?brainliest best answer.
Answer:
40 years
Step-by-step explanation:
I think 1 score is 20 years
so 2 scores = 2 x 20 = 40 years
I may be wrong so someone check
-Chetan K
the sum of two rational numbers is 17/18 If one of the numbers is 5/24 find the other number
Step-by-step explanation:
x + y = 17/18
x = 5/24
5/24 + y = 17/18
to bring both fractions to the same denominator (I see it is 72, but let's do it formally correct for you to learn), we look for the LCM, the lowest common multiple of both.
for this we split both numbers into their prime factors and then build the the combination of the longest chains per prime factor :
24 = 2×2×2×3
18 = 2×3×3
the LCM (and the new denominator) is then
2×2×2×3×3 = 8×9 = 72
so,
15/72 + y = 68/72
y = 53/72
53 is a prime number, so the fraction cannot be further refined.
What is the slope of the line that passes through the points (8, 2) and (9,3)? Write
your answer in simplest form.
Answer:
Well to calculate slope you just do
y2-y1/ X2-x1
In this case
9-8/3-2
Which is 1/1
THe slope is 1
Answer:
1
Step-by-step explanation:
The slope is going to be the ratio between the difference of y coordinates, and the difference in x coordinates.
[tex]m= \frac{\Delta y}{\Delta x} = \frac{3-2}{9-8} = \frac11 = 1[/tex]
In a class of 20 students, 5 have a brother and 11 have a sister. There are 3 students who have a brother and a sister. What is the probability that a student who does not have a brother has a sister?
The probability that a student who does not have a brother has a sister is 53.33%.
ProbabilityGiven that in a class of 20 students, 5 have a brother and 11 have a sister, and there are 3 students who have a brother and a sister, to determine what is the probability that a student who does not have a brother has a sister the following calculation must be performed:
20 - 5 = 10011 - 3 = X15 = 1008 = X8 x 100 / 15 = X800 / 15 = X53.33 = XTherefore, the probability that a student who does not have a brother has a sister is 53.33%.
Learn more about probability in https://brainly.com/question/13553988
plz help!
1. (0, y) , (2, 7); m = 1/2
y = _____
2. (4, 2) , (5, y) m = 4
y = _____
Answer:
Step-by-step explanation:
y = mx + b, where m is the slope and y the y-intercept (the value of y when x=0).
(0, y) , (2, 7); m = 1/2
We can start with y = (1/2)x + b
To find b, use one of the two given points. I'll use (2,7), since (0,y) isn't helpful.
y = (1/2)x + b
7 = (1/2)*2 + b
7 = 1 + b
b = 6
The equation is y = (1/2)x + 6.
Now find (0,y) by using x = 0:
y = 6
The second point is (0,6)
============
2. (4, 2) , (5, y) m = 4
y = mx + b
y = 4x + b
Use (4,2) and solve for b:
2 = 4*4 + b
b = -14
The equation is y = 4x - 14
Now find (5,y):
y = 4x - 14
y = 4*5 - 14
y = 20 - 14
y = 6
The second point is (5,6)
Se attached graph.
--