In a rectangle, the diagonals are equal. You need to set the two equal to each other. The line BE would be doubled to equal AC. Then solve: 2(2x-3)=3x+1 4x-6=3x+1 x=7 Now that you have x, you can find AC. Just plug it in. 3(7)+1 21+1 22 There you have it! AC=22
