# Math Help - Solving for the height of a table

1. ## Solving for the height of a table

To make a cardboard table for her dollhouse, Quisie uses a rectangular piece of cardboard measuring 40 inches wide and 60 inches long. She cuts four equal-sized squares from each corner and folds down the sides at a 90 degree angle. If the top of the table measures 800 square inches, how tall, in inches is the table?

A. 40
B. 30
C. 25
D. 20
E. 10

The answer is 10. I don't understand what the problem is asking me to do. The answer explanation says to plug in the answer choices, but I can't get a visual of the problem.

2. ## Re: Solving for the height of a table

Originally Posted by benny92000
To make a cardboard table for her dollhouse, Quisie uses a rectangular piece of cardboard measuring 40 inches wide and 60 inches long. She cuts four equal-sized squares from each corner and folds down the sides at a 90 degree angle. If the top of the table measures 800 square inches, how tall, in inches is the table?

A. 40
B. 30
C. 25
D. 20
E. 10

The answer is 10. I don't understand what the problem is asking me to do. The answer explanation says to plug in the answer choices, but I can't get a visual of the problem.
1. Draw a sketch.

2. The dimension of the table is length = 60 - 2x and width = 40 - 2x. Thus 0 < x < 20, (why?) where x is the height of the table.

3. According to the text you already now:

$(60-2x)(40-2x)=800$

Solve for x. You'll get 2 solutions but one solution can't be correct according to #2.