Question

Find the value of x.

Answer 1

This is a right triangle, so we know that:

h² = b' · c'

which is this case can be specificly written as:

BD² = AD · CD

BD² = 7 · 3 = 21

BD = √21

Now that we can also notice that ΔADB is also a right triangle, therefore we can apply the pythagorean theorem:

AD² + BD² = AB²

7² + (√21)² = x²

x² = 49 + 21 = 70

x = √70