CPM Homework Help : CCG Problem 8-72

Sandip noticed that when he looked into a mirror that was lying on the ground $8$ feet from him, he could see a clock on the wall. If Sandip’s eyes are $64$ inches off the ground, and if the mirror is $10$ feet from the wall, how high above the floor is the clock? Include a diagram in your solution.

Hint:

Draw a diagram:

2 right triangles share the vertex opposite vertical leg of each, triangle on left, has vertical leg on left, labeled 64 inches, & horizontal leg labeled 8 feet = 96 inches, triangle on right, has vertical leg on right, labeled height, & horizontal leg labeled 10 feet = 120 inches, angles at shared vertex, each has 1 tick mark.

Step 1:

Determine why the two triangles are similar. Remember triangles can be similar by AA, SAS, and SSS similarity theorems.

Step 2:

Set up a proportion. Are your units the same?

Step 3:

Solve the equation.