Question

The circumference of a circle is 8π inches. Show how you can use this information to calculate the same circle’s area.

Answer 1

c=2πr
a=πr²
common thing is r
hmm, solve for r in circumfernce
c=2π

`(c)/(2 \pi)`=r
sub that for r in other
a=πr²
a=π
`( (c)/(2 \pi))^2`
a=
`(c^2)/(4\pi)`

so
c=8π
a=
`((8\pi)^2)/(4\pi)`
a=
`(64\pi^2)/(4\pi)`
a=16π square inches