Let x=small circle
2x = bigger circle
πx^2 + π(2x)^2 = 80π
x^2 + 4x^2 = 80
5x^2 = 80
x^2 = 16
x = +/- 4
but we need the positive one because there's no negative measurement so
the answers are:
4m and 8m
3 2/5 x 2 1/3 rewrite
12/5 x 7/3 convert into fractions instead of mixed fraction then multiply straight across
84/15 would be your final answer you might need to reduce it though :) hope i helped
The answer is 2.8x! hope it helps