Math Geo help Ms Sue?
posted by Chase .
I have two questions about two circles.
A.First circle shows half a line measuring 4mm using 3.14 for pie. I came up with an answer that is wrong.:(
B.Second circle same pie but with a line all the way across the circle measuring 18cm. I got this one wrong?
Please help with steps on each? I want to understand what I got wrong so I can do better.

What questions are you trying to solve?
Circumference? Area? ?? 
area

A. Radius = 4
A = pi * r^2
A = 3.14 * 4^2
A = 3.14 * 16
A = 50.24 sq. cm.
B. Radius = 9 cm
Solve this the same was that I solved A. 
I really understand thank you.

You're welcome. :)