Question

Help!

In parallelogram ABCD, BE=10x-3 and DE=8x-1.


What is BD?


Question options:


7 units



14 units



21 units

Answer 1

14 units

Explanation:

The two halves of the diagonal are congruent, so ...

BE = DE

10x -3 = 8x -1

2x = 2 . . . . . . . add 3-8x

x = 1

BD = BE +DE = (10x -3) +(8x -1) = 18x -4

BD = 18·1 -4 = 14 . . . units

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It might be easier to figure DE = 8·1-1 = 7, then multiply by 2 to find BD = 14.