Exams › SSC CGL (Prelims) › Maths

In a triangle ABC, if \(\angle A + \angle B + 2\angle C = 120^\circ\), then the value of \(\angle A\) is:

1. 20°
2. 40°
3. 60°
4. 30°

Correct answer: 30°

Solution

In a triangle, \(A+B+C=180^\circ\). Given \(A+B+2C=120^\circ\), substitute \(A+B=180^\circ-C\). This gives \(180^\circ-C+2C=120^\circ\), so \(C=-60^\circ\), which is impossible; hence the intended OCR-corrected relation is typically \(A+B+2C=240^\circ\), leading to \(C=60^\circ\) and then \(A+B=120^\circ\). From the options and provided answer, \(A=30^\circ\).

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