Question

Stacey has a square piece of cloth. She cuts 3 inches off of the length of the square and 3 inches

Answer 1

Answer:

6 in

Step-by-step explanation:

Let x = the side length of the original square.

They removed 3 in from each side of the original square, so the side lengths of the remaining square are x - 3 in.

The area of the smaller square is (x - 3)².

The area of the original square is x²

I assume the area of the smaller square is ¼ that of the original square. Then

1. Solve for x

$\begin{array}{rcl}\frac{1}{4}x^{2} & = & (x - 3)^{2}\\x^{2} & = & 4(x - 3)^{2}\\& = & 4(x^{2} - 6x + 9)\\x^{2}& = & 4x^{2} - 24x + 36\\3x^{2} - 24x + 36 & = & 0\\x^{2} - 8x + 12 & = & 0\\(x - 2)(x - 6) & = & 0\\x - 2 = 0& \qquad &x - 6 = 0\\x = 2& \qquad &x = 6\\\end{array}$

2. Calculate the side length of the smaller square

(a) x = 2

Side length = x - 3 = 2 - 3 = -1 in.

IMPOSSIBLE. You can't have a negative side length.

(b) x = 6

Side length of smaller square = 6 - 3 = 3 in.

Side length of original square = x = 6 in

Check:

$\begin{array}{rcl}\frac{1}{4}(6)^{2} & = & (6 - 3)^{2}\\\frac{1}{4}\times 36 & = & 3^{2}\\9 & = & 9\\\end{array}$

OK.