# Ex.5.1 Q5 Lines and Angles Solution- NCERT Maths Class 7

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## Question

Find the angle which is equal to its supplement.

Video Solution
Lines & Angles
Ex 5.1 | Question 5

## Text Solution

What is known?

An angle which is equal to its supplement.

What is the unknown?

Find measure of the angle.

Reasoning:

Let us say given angle is $$x$$  and according to the question, its supplementary angle will also be equal to $$x$$. The sum of angle and its supplement angle is always equal to $$180^\circ.$$

Steps:

Let the angle be $$x.$$

Therefore, supplement of this angle will also be $$x.$$

We know that, the sum of measure of pair of supplementary angles is $$180 \,^{\circ}$$

\begin{align} x+x &=180^\circ\\ \Rightarrow2x &=180^\circ\\ \Rightarrow x&=(180^\circ)/2\\ \Rightarrow x&=90^\circ\end{align}

Thus, the angle which is equal to its supplement is $$90^\circ.$$

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