Answer:
Step-by-step explanation:
Problem One
Perimeter is in meters not square meters. The equation is
2*(6.8+x) + 2*12.5= 47 Remove the brackets. Combine like terms
13.6 + 2x + 25 = 47
38.6 + 2x = 47 Subtract 38.5 from both sides
2x = 47 - 38.6
2x = 8.4 Divide by 2
x = 4.2
Answer D
Problem 2
This problem is asking that you calculate the perimeter of a swimming pool.
The two semicircles on the ends make a whole circle.
The diameter of the semicircles is obtained from the difference of the two given lengths.
The rectangle has a length of 12. The length of the rectangle and the 2 semicircles is 16. The difference is 4. You could divide this by 2 to get the radius. I would just leave it as the diameter.
So the perimeter is pi*d + 2 * 12 [there are 2 lengths]
Perimeter = 4*pi + 24
Perimeter = 12.56 + 24
Perimeter = 36.56
Answer A
Problem 3
This is the circle inside the square.
The radius of the circle = 9
The diameter of the circle and the length of square's side = 2*9 = 18
The area of the square = s^2 where s = 18
The area of the square = 18^2 = 324
The area of the circle = pi * 9^2 = 3.24 * 81 = 251.34
The area of the Shaded area = 324 - 251.34 = 69.66
Answer C
Problem 4
b1 = 5
b2 = 11.5
h = 4.5
Formula
Area = (b1 + b2 ) * 4.5/2
Area = (5 + 11.5) * 4.5 /2
Area = 16.5 * 4.5 / 2
Area = 74.25/2
Area = 37.125
Answer D
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