Question

How do you find the area of a circle given the diameter but NOT the radius

Answer 1

So :

Area of circle = πr²

The diameter is two times the radius so you would divide the diameter by two.

For example if the diameter was 12cm, the radius would be 6cm. So then :
Area = π(6)²
Area = π(36)
Area = 113.04 cm²
This is an estimated answer because π is an irrational number.

Answer 2

`[(d)/(2)]^(2) = (pi) times ( (d^(2))/(4))= ((pi)d^(2))/(4)`area=pi times r^2
d=2r
r=d/2
subsitute
pi times
`[(d)/(2)]^(2) = (pi) times ( (d^(2))/(4))= ((pi)d^(2))/(4)`

area=
`((pi)d^(2))/(4)`