Question

The perimeter of a playing card is 30 centimeters. The area is 50 square centimeters. What are the dimensions of the playing card?

centimeters by
centimeters

Answer 1

Explanation:

We get two equations here. One for the area and one for the perimeter. The area gives us x×y=50. The perimeter, if we have a rectangle, x+y+x+y=30=2x+2y. For this to work we need to make a simple expression for x or y. Let's go with x here. 2x+2y=30 so x=15-y. if we fill that in the other equation we get (15-y)×y=50 (see picture). y=5 or y=10. If we fill in x×5=50 we get x=10 and vice versa. So the dimensions are 5 centimeters by 10 centimeters