The surface area of a sphere is given by the following formula:
V=4πr²
Except, pi in this case is approximately 22/7.
So, we will use a modified version where we substitute 22/7 in for π:
V=4(22/7)r²
Now, let’s plug in the values. The diameter is 70, and since the diameter is twice the radius, we can divide the diameter in half to find the radius.
70/2=35
So, r=35
V=4(22/7)(35)²
V=15,400cm
So, the surface area of the sphere is 15,400cm.