4
Step-by-step explanation:
4 x 3 = 12
4 x 5 = 20
2 x 6 = 12
2 x 10 = 20
(4 is greater than 2 though)
5 x ? = 12
5 x 4 = 10
6 x 2 = 12
6 x ? = 20
use formula for the circle a=3.14
step-by-step explanation: