#### Chapter 14 Quadrilaterals R.D. Sharma Solutions for Class 9th Exercise 14.1

**Exercise 14.1**

1. Three angles of a quadrilateral are respectively equal to 110°, 50° and 40°. Find its fourth angles.

**Solution**

2. In a quadrilateral ABCD, the angles A, B, C and D are in the ratio 1 : 2 : 4 : 5. Find the measure of each angles of the quadrilateral.

**Solution**

**Solution**

4. The angles of quadrilateral are in ratio 3:5:9:13. Find all angles of the quadrilateral.

**Solution:**

We know that sum of all angles of a triangle is 360°

It is given; angles are in ratio 3:5:9:13. So, we can say, the angles are 3x, 5x, 9x and 13x.

Sum of all angles

3x+5x+9x+13x = 360°

⇒30x=360°

⇒x = 360°/30 = 12°

So, angles are

3x = 3×12°=36°

5x = 5×12°=60°

9x =9×12°= 108°

13x =13×12°=156°

So, angles are 36°, 60°,108°, 156°