Important Questions for Chapter 6 - Lines and Angles

If you are preparing for the final exam or any competitive exam, we have come up with the important CBSE questions along with the solutions for class 9. Practice these questions and score more in your exams

Important questions based on NCERT syllabus for Chapter 6 - Lines and Angles:

Question 1: An angle is equal to one-third of its supplement. Find its measure.
Solution:
Let the measure of the required angle be x degrees. Then,
It's supplement =180∘−x
It is given that
x=1/3(180∘−x)
3x=180∘−x
4x=180∘
x=45∘
Thus, the measure of the given angle is 45∘.

Question 2: Find the measure of the supplementary angle of the following angles :
(i) 45∘
(ii) 57∘
Solution:
We know that the measure of the supplementary angle of x∘ is equal to (180∘–x∘).
(i) Measure of the supplementary angle of 45∘
= 180∘ – 45∘ = 135∘

(ii) Measure of the supplementary angle of 57∘
= 180∘ – 57∘ = 123∘

Question 3: Find the supplement of the following angle:
134∘ 30’ 26′”
Solution:
Supplement of an angle of 134∘ 30’ 26′”
=180∘–(134∘ 30’ 26′”)
=(179∘–134∘)+(1∘–30′ 26′′)
=45∘+(60′–(30′+26′′)) [1∘=60′]
=45∘+(59′–30′)+(1′–26′′)
=45∘+29′+34′′
=45∘ 29′ 34′′