Question

One angle of an isosceles trapezoid has measure 57. What are the measures of the other angles?

Answer 1

In an isosceles trapezoid the two adj angles are equal
& the two opposite angles are equal & the
sum of the interior angles =360
so      57 + 57 = 114
360-114 = 246
the other angles are  246/2    = 123
the measure of the other angles are        57,123 & 123

Answer 2

$\alpha =57^o\\ \\ The \ interior \ angle \ at \ the \ shortest \ base \ is \ equal \ to :\\ \\ \beta = 180^o - 57^o = 123^o$