Exercise 5.1

Property: The total sum of the measures of all the three angles of a triangle is 180°.

Instruction

1. Is it possible to have a triangle with the following sides?

(i) 3 cm, 4 cm and 5 cm.

Solution:

To form a triangle, the sum of any two sides must be greater than the third side.

3 + 4 = > 5

3 + 5 = > 4

4 + 5 = > 3

, we can form a triangle with these sides.

(ii) 6 cm, 6 cm and 6 cm.

Solution:

Let's check: 6 + 6 = > 6

6 + 6 = > 6

, we can form a triangle with these sides.

(iii) 4 cm, 4 cm and 8 cm.

Solution:

Let's check: 4 + 4 = = 8

4 + 8 = > 4

, we cannot form a triangle with these sides because 4 + 4 = 8.

(iv) 3 cm, 5 cm and 7 cm.

Solution:

Let's check: 3 + 5 = > 7

3 + 7 = > 5

5 + 7 = > 3

, we can form a triangle with these sides.

The Triangles and its Properties