**Chapter 4 Basic Geometrical Ideas Ex 4.4**

Question 1.

Draw a rough sketch of a triangle ABC. Mark a point P in its interior and a point Q in its exterior. Is the point A in its exterior or in its interior?

Solution:

Triangle ABC is the given triangle.

P is in the interior of ∆ABC.

Q is in the exterior of ∆ABC.

A is neither in the exterior nor in the interior.

Question 2.

(a) Identify three triangles in the figure.

(6) Write the names of seven angles.

(c) Write the names of six line segments.

(d) Which two triangles have ∠B as common?

Solution:

(a) Three triangles are: ∆ABC, ∆ABD and ∆ADC.

(b) (i) ∠ABC

(ii) ∠ADB

(iii) ∠BAD

(iv) ∠ADC

(v) ∠ACD

(vi) ∠DAC

(vii) ∠BAC.

(c) ∆ABC and ∆ABD have ∠B as common.