CAT Quantitative Aptitude Questions | Geometry Questions for CAT - Triangles

The question is from the topic triangles. It discusses about incenter of a triangle. CAT Geometry questions are heavily tested in CAT exam. Make sure you master Geometry problems. Two angles of a triangle is given, we need to find out the angle made by incenter and vertices.

Question 20: Triangle ABC has angles A = 60^° and B = 70^°. The incenter of this triangle is at I. Find angle BIC.

1. 90^°
2. 130^°
3. 80^°
4. 120^°

Explanatory Answer

Method of solving this CAT Question from Triangles: What is an incenter? Clue - It has something to do with angle bisectors.

A + B + C = 180 in a triangle
Hence C = 180 – 130 = 50^°
Incenter is the meeting point of angle bisectors. BIC will form a triangle.
In this triangle B = 35, C = 25
Hence BIC or I = 180 – (35 + 25) = 120^°

The question is "Find angle BIC."

Hence, the answer is 120^°.

Choice D is the correct answer.