Question

In quadrilateral ABCD, AD // BC. What must the length of segment AD be for the quadrilateral to be a parallelogram?

8 units
16 units
31 units
62 units
​

Answer 1

31 units

Explanation:

Since the given shape is a parallelogram |AD| = |BC|

3x + 7 = 5x - 9 transfer like terms to same side of the equation

7 + 9 = 5x - 3x add/subtract like terms

16 = 2x divide both sides by 2

8 = x replace x with the value so we can calculate the length of AD

3*8 + 7 = 31