Q5 of 97 Page 205

Can we construct a ∆ABC in which AB=5cm, BC=4cm and AC=9cm? Why?

We know that,

The sum of two sides must be greater than the third side

In this case, we have

AB + BC = 5 + 4 = 9 cm

AC = 9 cm

∴ AC must be greater than the sum of AB and BC

Hence, the sum of two sides is not greater than the third side. So, cannot be constructed

In a right ∆ABC, ∠B=90°. Find the longest side.

In a ∆ABC, ∠B > ∠C. Which of AC and AB is longer?

Find the measure of each exterior angle of an equilateral triangle.

Show that the difference of any two sides of a triangle is less than the third side