*note: for this problem you have to round a few values. I rounded to 2 decimal places, but your answer could be different if you have to round to more/less than 2 decimal places
Answer: Diameter = 8 millimeters
Buttons are circles, so we will use the formula for area of a circle:
A = πr^2
We are solving for the diameter, which is 2 times the radius:
d = 2r
So now we plug in what we know.
The area A = 50.24 square millimeters, therefore we plug it in and simplify:
50.24 square millimeters = πr^2
50.24/π = r^2
15.99 = r^2
squareroot(15.99) = r
r = 4 millimeters
Now we use the radius to calculate the diameter.
r = 4 millimeters
d = 2r
d = 2(4)
diameter = 8 millimeters