A.
This is because in each circle the lines increase by one, so from the triangle (3 lines) to the rectangle (4 lines) it only makes sense to put a pentagon (5 lines)
1:2=3:6
the missing number is 6
:)
Imposible triangle, lagest side must be > sum other sides.
put the decimal in the multiplication problem in the exact same point under the line then multiply as normal and you should get 152.6 meaning $152.60
You can think of this equation as

and thus apply the transformations to it as such



1) D = 2, C = +3
2) D = -12, C = -2
3) C = +6, D = 3
4) C = -7, D = -7