This is what i got when i worked it out
Step-by-step explanation:
always write what you know
circumference
U = 2 x pi x r
r = d/2
U = 39.25
rearrange and solve for r
U / (2 x pi) = r
solve for diameter
2r = d
Answer:
4n^2 + 22n
Step-by-step explanation:
10(n^2+n) -6 (n^2 - 2)
10n^2 + 10n - 6n^2 + 12
4n^2 + 22n