(x+1)2-
=it is meant to be (x+1)2
=2(x) + 2(1)
= 2x +2
I think
It usually works well to do what the instructions tell you. Multiply each diameter by 3.14.
a) 3.14×6 cm = 18.84 cm
b) [can't read the picture]
d) 3.14×9 in = 28.26 in
e) 3.14×11 mm = 34.54 mm