The vertex angle of an isosceles triangle measures 20 degrees more than twice the measure of one of its base angles. How many degrees are there in a base angle of this triangle?

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Answer 1 · 2016-11-24T06:57:50

The base angles are $40°$

Let the the size of each base angle be $x$ .

The vertex angle is twice $x$ , with another $20°$
Vertex angle = $2x+20°$

The sum of the three angles in a triangle is always 180°

$x+x+x^2+20° = 180" "larr$ now solve the equation

$4x+20° = 180°$

$4x = 180°-20°$
4x = 160°#

$x = 160/4$

$x = 40°$

The angles are $40°, 40° and 100°$