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# Ex.5.1 Q3 Lines and Angles - NCERT Maths Class 7

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## Question

Identify which of the following pairs of angles are complementary and which are supplementary:

(i) $$65^\circ, 115^\circ$$

(ii) $$63^\circ, 27^\circ$$

(iii) $$112^\circ, 68 ^\circ$$

(iv) $$130^\circ, 50^\circ$$

(v) $$45^\circ, 45^\circ$$

(vi) $$80^\circ, 10^\circ$$

NOTE: The sum of the measure of complementary angle is $$90^\circ$$ and that of supplementary angle is $$180^\circ$$

Video Solution
Lines & Angles
Ex 5.1 | Question 3

## Text Solution

Reasoning:

Find out the sum of two given angles,and then check whether it is $$180^\circ$$ or $$90^\circ.$$ If  the sum of two angles is either equal to $$90^\circ$$, the angles are complementary and if the sum of the two angles is $$180^\circ$$, the angles are complementary.

Steps:

Solve for supplementary angle or complementary angle:

(i) $$65^\circ, 115^\circ$$

Sum of measure of these two angles $$= 65^\circ + 115^\circ = 180^\circ$$

Therefore, these two angles are supplementary.

(ii) $$63^\circ, 27^\circ$$

Sum of measure of these two angles $$= 63^\circ + 27^\circ = 90^\circ$$

Therefore, these two angles are complementary.

(iii) $$112^\circ, 68^\circ$$

Sum of measure of these two angles $$= 112^\circ + 68^\circ = 180^\circ$$

Therefore, these two angles are supplementary.

(iv) $$130^\circ, 50^\circ$$

Sum of measure of these two angles $$= 130^\circ + 50^\circ = 180^\circ$$

Therefore, these two angles are supplementary.

(v) $$45^\circ, 45^\circ$$

Sum of measure of these two angles $$= 45^\circ + 45^\circ = 90^\circ$$

Therefore, these two angles are complementary.

(vi) $$80^\circ, 10^\circ$$

Sum of measure of these two angles $$= 80^\circ + 10^\circ = 90^\circ$$

Therefore, these two angles are complementary.

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