Question

An isosceles triangle has an angle that measures 138º. Which other angles could be in that

isosceles triangle? Choose all that apply.
21°
20°
700
8°

Answer 1

Let the two equal angles be x,

so,

x + x + 138° = 180°

or, 2x = 180° - 138°

or, 2x = 42°

so, x = 42°/2

so, x = 21°

21° is the answer.