An Isosceles triangle has two sides and two angles to be congruent or equal.
Let the two congruent angles be x° degrees, then the third side which is 57° greater than the congruent angles would measure (x+57°).
SKETCH
The sum of angles in a triangle is 180°. Hence,
Therefore, the measure of all three angles are: 41,⁰ 41⁰, and 98⁰