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jmc

prealgebra senior

Problem

On the 5 by 5 square grid below, each dot is 1 cm from its nearest horizontal and vertical neighbors. What is the product of the value of the area of square (in cm) and the value of the perimeter of square (in cm)? Express your answer in simplest radical form.

problem


Note that when we say the grid is 5 by 5 we mean that each row and column contains 5 dots!
Solution
Applying the Pythagorean theorem to the right triangle whose hypotenuse is AD and whose legs are dashed in the diagram below, we find that the side length of the square is centimeters. Therefore, the area of the square is square centimeters and the perimeter of the square is centimeters. The product of these two values is cubic centimeters.
Final answer
40\sqrt{10}