Question

Apply the properties of isosceles and equilateral triangles to find the unknown angles in the given figure:

Answer 1

In fig.,

a + b + 40° = 180° ........(Angles of a triangle)

⇒ a + b = 180° − 40° = 140°

But a = b ..........(Angles opposite to equal sides)

∴ a = b =`(140°)/2=70°`

∴ x = b + 40° = 70° + 40° = 110° .........(Exterior angle of a triangle is equal to the sum of its interior opposite angles)

Similarly y = a + 40°

= 70° + 40° = 110°

Hence x = 110°, y = 110°