Question

The area of a circle is 78.5 cm2. What is the diameter of the circle?

Answer 1

Your answer is 157, i'm pretty sure

Answer 2

hello : 
The area of a circle is : A = π × r² 
r² = A/π 
r² = 78.5/3.14
r² = 25
r = 5
but : d = 2r    ... r : ridus and  d : the diameter
so : d= 10