Given: aklm is a trapezoid, ak=13
lm=14, kl=5, am=20
find: h

  h = 11.2

Step-by-step explanation:

Let point M' be a point on AM that is 5 units toward point A from M. Let point B lie on AM such that KB⊥AM. Let x = AB; then BM' = 15 -x. The Pythagorean theorem gives rise to two equations in x and h:

Subtracting the first from the second gives ...

  (225 -30x +x² + h²) - (x² + h²) = 196 -169

  225 -30x = 27

  x = 198/30 = 6.6

Then ...

  h = √(13² -x²) = √(169 -43.56) = √125.44

  h = 11.2

a 10 percent increase