Question

The figure below shows Daniel’s semi-circular patio. The shaded region represents the tiled portion of the patio.



The width of the tiled portion is 1.5 feet. What is the area of the tiled portion of the patio, rounded to the nearest whole square foot?

5 square feet

25 square feet

7 square feet

42 square feet

Answer 1

First, figure out the area of the entire semicircle. Since the diameter is 12, the radius is 6, so the area is 18 pi. (6^2 pi, but divided by 2 because it's a semicircle.) Then, you want to figure out the area of the non-tiled portion. If the tiled portion is 1.5 feet wide, then you will subtract 3 from the diameter (because there are two tiled portions in the diameter), getting a diameter of 9 for the center portion. Calculate the area to get 10.125 pi. Then, subtract the center from the whole thing, to get 7.875 pi, which is roughly 25 square feet.

Answer 2

figure the area of the entire semi-circle 1st.

a=pi*r^2

Answer 3

thank you!