16Hit1600
Geometry and TrigonometryEasy–MediumLadder against a wall

Geometry and Trigonometry practice question

A ladder 10 feet long leans against a vertical wall, with its foot on level ground 6 feet from the base of the wall. How many feet up the wall does the ladder reach?

Answer: 8

The wall, the ground and the ladder form a right triangle with hypotenuse 10 and one leg 6. The other leg is √(10² − 6²) = √(100 − 36) = √64 = 8.

Common wrong answers

If you answered 4
4 is 10 − 6. Lengths in a right triangle don't subtract directly; the squares do: 100 − 36 = 64.
If you answered 16
16 is 10 + 6, but the height must be shorter than the ladder itself.
If you answered 136
136 is 10² + 6², adding the squares — that finds a hypotenuse. Here 10 IS the hypotenuse, so subtract: 100 − 36.

More Geometry and Trigonometry questions

Not affiliated with the College Board. SAT is a trademark of the College Board.