In similar figures sides are in proportion
The sides of the bigger parallelogram are x+8 and 20
The sides of smaller parallelogram are x and 12
The sides are in proportion
[tex] \frac{x+8}{x} =\frac{20}{12} [/tex]
We can solve this for x
To solve for x we cross multiply
20x=12(x+8)
20x=12x+96
Subtracting 12x both sides
20x-12x=96
8x=96
Dividing both sides by 8
x=12
