Question 1. In parallelogram ABCD, ∠A = 3 times ∠B. Find all the angles of the parallelogram. In the same parallelogram if AB = 5x – 7 and CD = 3x + 1; find the length of CD. Solution:- Let ∠B=x ∠A=3∠B=3x AD||BC ∠A+∠B=180° 3x+x=180° ⇒4x=180° ⇒x=45° ∠B=45° Opposite angles of parallelogram are equal. ∠A=∠C=135°