On a sunny day, a classmate uses indirect measurement to find the height of a building. The building's shadow is 12 ft long and your classmate's shadow is 4 ft long. If your classmate is 5 ft tall, what is the height of the building?

15 feet tall.

Step-by-step explanation:

To find the height of a building, we can set up a ratio as shown:

Cross multiply to begin solving for 'x':

4x = 60

Divide '4' by both sides:

x = 15 ft.

+25 = x

step-by-step explanation:

here x is the hypotenuse of a right triangle whose legs are 7 and 24.   by the pythagorean theorem, 7² + 24² must equal x²:

x² = 49 + 576 = 625.   thus, x = +√625 = +25 = x