Question

Angles of a triangle are in ratio 1 : 5 : 12, the biggest angle of this triangle is:

• A. 60°
• B. 120°
• C. 90°
• D. 45°

Hint:

For triangles with angles in a given ratio, let the angles be expressed in terms of a variable, and use the fact that the sum of the angles in a triangle is always \( 180^\circ \).

Answer 1

The Correct Option is B

The sum of the angles of a triangle is \( 180^\circ \). Let the angles of the triangle be \( x \), \( 5x \), and \( 12x \). Then: \[ x + 5x + 12x = 180^\circ \] \[ 18x = 180^\circ \quad \Rightarrow \quad x = 10^\circ \] Thus, the angles of the triangle are: \[ x = 10^\circ, \quad 5x = 50^\circ, \quad 12x = 120^\circ \] The biggest angle is \( 120^\circ \). Therefore, the correct answer is \( 120^\circ \).