6Ladder, Pythagorean theorem

A 10 ft ladder leans against a wall with its foot 6 ft from the base of the wall. How high up the wall does it reach?

The ladder reaches 8 ft up the wall. Using the Pythagorean theorem, 6² + h² = 10², so h² = 100 − 36 = 64, and h = √64 = 8 ft. Check: 6² + 8² = 100 = 10² ✓.