what is the circumference of a circle that has an area of 144m^2? round to the nearest 10th

Question

Use 3.14 for pi

Answer 1

Area = 3.14 x r^2

Circumference = 3.14 x D

Where r = radius and D = diameter

We also know that D = 2r

 

And since for circle Area = 114

114 = 3.14 x r^2

 

And since D = 2r , r = D/2

So,   (D/2)^2 x 3.14 = 114

(D^2) / (2)^2 = 114 / 3.14

D^2 = (114 x 2^2) / 3.14 = (114 x 4) / 3.14

D^2 = 456/3.14

D = (456/3.14)^(1/2) = (145.22)^(1/2)

D = 12.05

 

And so now since  C = circumference = 3.14 x D

C = 3.14 x 12.05 = 37.837

 

And this answer rounded to the nearest tenth is 37.8m