Therefore, the length of AC in the isosceles trapezoid ABCD is 16. In the trapezoid KLMN, NM is equal to x + 4 and KL is equal to x + 8. In the trapezoid ABCD, m∠A is equal to 2x + 10 and m∠B is equal to 3x - 20. In the trapezoid ABCD, m∠A is equal to 2x + 15 and m∠B is equal to 4x - 11. In the trapezoid ABCD, m∠D is equal to x + 15 and m∠C is equal to 2x - 85. In the trapezoid ABCD, m∠C is equal to 3y + 12 and m∠D is equal to 2y + 50.