Question

The base of a 20-foot ladder is placed 12 feet from a building. How far up on the building does the ladder reach?

16 ft
8 ft
23 ft
4 ft

Answer 1

Explanation:

16ft

Answer 2

answer is:

16 feet.

Explanation:

We are given that:

The base of a 20-foot ladder is placed 12 feet from a building.

Now we re asked to find how far up on the building does the ladder reach?

i.e. we can consider a right angled triangle such that the base is given to be 12 feet.

the length of hypotenuse is given to be= 20 feet.

Now we are asked to find the height of a right angled triangle.

Let us consider ΔABC.

such that ∠B=90°, BC=12 feet, AC=20 feet

Now we can use pythagorean theorem to find out the length of side AB.

`AC^(2)=AB^(2)+ BC^(2)\\\\AB^(2)=AC^(2)-BC^2\\\\AB^2=(20)^2-(12)^2\\\\AB^2=400-144\\\\AB^2=256\\\\AB=16`

Hence, ladder is 16 feet above the ground level.