Question

If one of the base angles of an isosceles triangle is 40°, then the vertical angle is equal to: a)60° b ) 120 ° c) 100 ° d)40 °

Answer 1

Ans - we know that In isoscele triangle

there is opposite sides are equal and opposite angle are also equal

solution start from there

we know that the sum of all interior ange of triangle is 180

let the vertical angle be A

now, A+40+40 = 180

A= 180-80

A = 100

so, vertical angle be 100 °

option c is correct