The area of a circle is:
A=πr²
simply π as 3.14 or we could just leave it there and r is the radius.
Diameter is not a radius but simply twice the radius so, divide it by 2
D=2r
14 dm=2r
r=7 dm
Substitute
A=πr²
A=π(7 dm)²
A=49π dm²
If your professor doesn't consider π as a variable multiply by 3.14
A=49(3.14) dm²
A=153.86 dm²
Hope this helps =)
