# Ex 5.1, 7 - Chapter 5 Class 7 Lines and Angles

Last updated at Sept. 11, 2018 by Teachoo

Last updated at Sept. 11, 2018 by Teachoo

Transcript

Ex 5.1, 7 Can two angles be supplementary if both of them are: (i) acute? We know that If two angles are supplementary, their sum is 180°. If both angles are acute Angle 1 < 90° Angle 2 < 90° Example: 30 ° & 85° 30° + 85 ° = 115° ≠ 180° Since sum is not 180°, they are not supplementary Let’s take another example. If Angles are 89° & 89° 89° + 89° = 178° ≠ 180° Since sum is not 180°, they are not supplementary Ex 5.1, 7 Can two angles be supplementary if both of them are: (ii) obtuse? We know that If two angles are supplementary, their sum is 180°. If both angles are obtuse Angle 1 > 90° Angle 2 > 90° Example: 100 ° & 120° 100° + 120° = 220° ≠ 180° Since sum is not 180°, they are not supplementary Let’s take another example. If Angles are 91° & 91° 91° + 91° = 182° ≠ 180° Since sum is not 180°, they are not supplementary Ex 5.1, 7 Can two angles be supplementary if both of them are: (iii) right? We know that If two angles are supplementary, their sum is 180°. If both the angles are right angles. Angle 1 = 90° Angle 2 = 90° Here, Angle 1 + Angle 2 = 90° + 90° = 180° Since, sum of both angles is 180° So, they are supplementary.

Ex 5.1

Ex 5.1, 1 (i)

Ex 5.1, 1 (ii)

Ex 5.1, 1 (iii)

Ex 5.1, 2 (i)

Ex 5.1, 2 (ii)

Ex 5.1, 2 (iii)

Ex 5.1, 3 (i)

Ex 5.1, 3 (ii)

Ex 5.1, 3 (iii)

Ex 5.1, 3 (iv)

Ex 5.1, 3 (v)

Ex 5.1, 3 (vi)

Ex 5.1, 4 Important

Ex 5.1, 5

Ex 5.1, 6 Important

Ex 5.1, 7 You are here

Ex 5.1, 8 Important

Ex 5.1, 9 Important

Ex 5.1, 10

Ex 5.1, 11

Ex 5.1, 12 (i)

Ex 5.1, 12 (ii) Important

Ex 5.1, 13 (i) Important

Ex 5.1, 13 (ii)

Ex 5.1, 13 (iii)

Ex 5.1, 13 (iv)

Ex 5.1, 13 (v)

Ex 5.1, 13 (vi)

Ex 5.1, 14 Important

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.