Theorem 8.5 - Chapter 8 Class 9 Quadrilaterals

Last updated at May 29, 2023 by

Theorem 8.5 - Class 9 - If both pair of opposite angles are equal.jpg

Theorem 8.5 - Chapter 8 Class 9 Quadrilaterals - Part 2
Theorem 8.5 - Chapter 8 Class 9 Quadrilaterals - Part 3

Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class

Book a free demo

Transcript

Theorem 8.5 If in a quadrilateral, each pair of opposite angles is equal, then it is a parallelogram. Given : ABCD is a quadrilateral with opposite angles equal, i.e. 1 = 3 & 2 = 4 To Prove : ABCD is a Parallelogram Proof : By angle sum property of quadrilateral 1 + 2 + 3 + 4 = 360 1 + 2 + 1 + 2 = 360 2( 1 + 2) = 360 1 + 2 = 360 2 1 + 2 = 180 Similarly we can prove that, 1 + 4 = 180 Thus, In ABCD, Both pairs of opposite sides are parallel, ABCD is a parallelogram

Ask a doubt
Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.