Question

A 13 foot ladder is resting against a house. The base of the ladder is 5 feet from the base of the wall.

How high up the wall does the ladder reach? First step is to draw a diagram of the problem.
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Answer 1

This is just the application of Pythagoras theorem

To find how high up the wall the ladder reach

⇒ 13^2 = x^2 + 5^2

therefore x^2 = 13^2 - 5^2

x^2 = 169 -25

x^2 = 144

x = 12

therefore the ladder is 12 foot high up the wall

Explanation: