Answer: 12 feet up
Step-by-step explanation:
This problem models a right triangle, in which the ladder is the hypotenuse and the distance away from the wall is one of the legs. Thus, you may use the Pythagorean Theorem (a^2 + b^2 = c^2)
<u>N.B. There are some very useful sets of numbers that can help you with this unit</u>.
<u>They are called Pythagorean triplets, and they are the sets of whole numbers that make right triangles.</u> The important ones are 3, 4, 5, and 5, 12, 13 (And their multiples, like 6, 8, 10(3,4,5 *2))
Hope it helps :) and let me know if you want me to elaborate further.