Last updated at Aug. 31, 2021 by Teachoo

Transcript

Ex 3.3, 3 Can a quadrilateral ABCD be a parallelogram if (i) ∠D + ∠B = 180°?Given a quadrilateral ABCD where ∠D + ∠B = 180° If ABCD is a parallelogram, then Opposite angles of a Parallelogram are equal ∴ ∠B = ∠D Given, ∠D + ∠B = 180° Putting ∠ D = ∠ B ∠B + ∠B = 180° 2∠B = 180° ∠ B = (180°)/2 ∠B = 90° ∴ ∠B = ∠D = 90° So, ABCD is a parallelogram where ∠B = ∠D = 90° which is possible only if ABCD is a square or a rectangle ∴ ABCD may be a parallelogram, But not in all cases.

Ex 3.3

Ex 3.3, 1

Ex 3.3, 2 (i) Important

Ex 3.3, 2 (ii)

Ex 3.3, 2 (iii)

Ex 3.3, 2 (iv)

Ex 3.3, 2 (v)

Ex 3.3, 3 (i) Important You are here

Ex 3.3, 3 (ii)

Ex 3.3, 3 (iii)

Ex 3.3, 4

Ex 3.3, 5 Important

Ex 3.3, 6

Ex 3.3, 7

Ex 3.3, 8 (i)

Ex 3.3, 8 (ii)

Ex 3.3, 9 Important

Ex 3.3, 10

Ex 3.3, 11

Ex 3.3, 12 Important

Chapter 3 Class 8 Understanding Quadrilaterals

Serial order wise

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.