The sum of the measures of the angles is 180° in a triangle.
An isosceles triangle has 2 equal sides and 2 equal angles.
Mark equal angles with θ.
So:
40° + θ + θ = 180°
40° + 2 θ = 180°
Subtract 40° to both sides
2 θ = 140°
Divide both sides by 2
θ = 70°
In this triangle the angles are:
40° , 70° , 70°
In an isosceles triangle is one of the angles 40∘. What values are possible for the outer angles.
(not asking help from Writeacher) only oobleck
2 answers
The other possibility is, of course,
40°, 40°, 100°
40°, 40°, 100°
1 answer