Question

Assertion: If two angles of a triangle measure 50° and 70°, its third angle is 60°.
Reason: The sum of the angles of a triangle is 180°.
(a) Both Assertion and Reason are true and Reason is a correct explanation of Assertion.
(b) Both Assertion and Reason are true but Reason is not a correct explanation of Assertion.
(c) Assertion is true and Reason is false.
(d) Assertion is false and Reason is true.

Answer 1

(a) Both Assertion and Reason are true and Reason is a correct explanation of Assertion.

Assertion:
Let the third angle be $x°$.
Then,
$$\begin{gathered} 50°+70°+x°=180°\left[\text{Sum of the angles of a triangle}\right] \\ \Rightarrow x°=\mathbf{60}\mathbf{°} \end{gathered}$$
Hence, the Assertion is true.
Reason:
Clearly, the given statement is true.
Since, both the Assertion and Reason are true and Reason is a correct explanation of Assertion.