Question

Find the variable of the isosceles triangle having a vertex of 40° and one given angle as 2x.

Answer 1

x = 35

Explanation:

the base angles of an isosceles triangle are congruent, both 2x

the sum of the 3 angles in a triangle = 180°

sum the 3 angles and equate to 180

2x + 2x + 40 = 180

4x + 40 = 180 ( subtract 40 from both sides )

4x = 140 ( divide both sides by 4 )

x = 35