Question

5 STARS 20 foot ladder is leaning against the side of a building the bottom of the ladder is 4 feet from the wall the bottom of the ladder is 4 feet from the wall how many feet above the ground does the ladder touch the wall

Answer 1

400

The ladder is the hypotenuse of a right triangle. The 2 feet from the wall on the ground is one side, the distance up the wall is another side.

In a right triangle, the square of the hypotenuse is the sum of the squares of the other two sides. This is called the Pythagorean Theorem. In equation form:

c^2 = a^2 + b^2

Substitute the known values:

20^2 = 2^2 + b^2

Square the numbers:

400 = 4 + b^2

Subtract 4 from both sides:

b^2 = 400 - 4 = 396

Take the square root:

b = sqrt(396) = 19.9 (rounded) feet

Check:

20^2 ?= 2^2 + 19.9^2

400 ?= 4 + 396.01

400 ?= 400.01 (off just a bit due to rounding)