Daniel cut a square cake vertically to make two rectangle slices. Each rectangle had a perimeter of 45 inches. How long is each side of the original square cake?

15 inches

Step-by-step explanation:

As the square cake was cut in two equal pieces, we have that one side of the rectangle is the double of the other side, so we have that:

2*Length + 2*Width = 45

Length = 2*Width

So using the value of length in the first equation, we have:

4*Width + 2*Width = 45

6*Width = 45

Width = 7.5

Length = 2*Width = 15

So each side of the original cake is equal to the length of the rectangle pieces, that is, 15 inches.