Question

In the neighborhood park there is a circular grassy picnic area, but half of the grass has died. The city wants to replant the grass, but needs to know the square footage of the damaged area. If the circular picnic area is 150 feet across, what is the square footage of the damaged area? Let π = 3.14.
A) 471 sq. feet
B) 8831.25 sq. feet
C) 17662.5 sq. feet
D) 35325 sq. feet

Answer 1

so, πr^2 is the equation for the area of a circle, if we calculate that, it will equal 17662.5

we then half that to get the area (square feet) of the dead grass, which is 
8831.25 square feet which means the answer is B.

Answer 2

150 feet across is diameter
find area
but 1/2 is dead
find area then times 1/2

area=pir^2

150=d
d/2=r=150/2=75=r

area=pi75^2
area=5625pi
times 1/2
area=2812.5pi
pi=3.14 for this problem
area=8831.25

B is answer