Question

What are the lengths of side AB and side BC?

Answer 1

AB = 20

BC = 14

Explanation:

ABCD is a parallelogram

Opposite sides of a parallelogram are equal.

Therefore,

AB = DC

3x - 7 = x + 11

3x - x = 11 + 7

2x = 18

x = 18/2

x = 9

AB = 3x - 7 =3*9 - 7 = 27 - 7 = 20

7y - 7 = 3y + 5

7y - 3y = 7 + 5

4y = 12

y = 12/4

y = 3

BC = 7y - 7 = 7*3 - 7= 21 - 7 = 14

Answer 2

Answer: AB=20, BC=14

Explanation:

set AB together with the side congruent to it (which is DC)

3x-7=x+11

subtract x and add 7 to both sides

2x=18

divide both sides by 2

x=9

plug 9 in for AB.

3(9)-7

27-7=20.

now do the same for BC