Question

If AD = 12 units, BD = 15 units, and AC = 4 units, what is the length of BC?

Answer 1

The answer to your question is: BC = √65 or 8.05 u

Explanation:

Data

AD = 12 u

BD = 15 u

AC = 4 u

BC = ?

First calculate the length of AB using the pythagorean theorem

BD² = AB² + AD²

AB² = BD² - AD²

AB² = 15² - 12²

AB² = 225 - 144

AB² = 81

AB = 9 u

Now, use the pythagorean theorem to find BC

AB² = BC² + AC²

BC² = AB² - AC²

BC² = 9² - 4²

BC² = 81 - 16

BC² = 65

BC = √65 or 8.05 u