37292827 the answer is that
Circumference is equal to diameter multiplied by pi. C=d X pi. To find the radius we need to rearrange this equation. We know what pi and the circumference are, so to find diameter we do circumference divided by pi. D=c/pi. 942/pi = 299.85. This gives us the diameter, for the radius simply divide by 2 which is 149.92 :)
7(a - 10) = 13 - 2(2a + 3)
7a - 70 = 13 - 4a - 6 = 7 - 4a
7a + 4a = 7 + 70
11a = 77
a = 77/11 = 7
a = 7.