The measure of one angle of an isosceles triangle is $50^{\circ}$. The measures of the other angles in this triangle could be
(A) $50^{\circ}$ and $90^{\circ}$
(D) $30^{\circ}$ and $100^{\circ}$
(B) $40^{\circ}$ and $50^{\circ}$
(E) $60^{\circ}$ and $70^{\circ}$
(C) $50^{\circ}$ and $80^{\circ}$
The sum of the three angles in any triangle is $180^{\circ}$.

If one of the angles in an isosceles triangle measures $50^{\circ}$, then the sum of the measures of the two unknown angles in the triangle is $180^{\circ}-50^{\circ}=130^{\circ}$.

Since the triangle is isosceles, then two of the angles in the triangle have equal measure.

If the two unknown angles are equal in measure, then they each measure $130^{\circ} \div 2=65^{\circ}$.

However, $65^{\circ}$ and $65^{\circ}$ is not one of the given answers.

If the measure of one of the unknown angles is equal to the measure of the given angle, $50^{\circ}$, then the third angle in the triangle measures $180^{\circ}-50^{\circ}-50^{\circ}=80^{\circ}$.

Therefore, the measures of the other angles in this triangle could be $50^{\circ}$ and $80^{\circ}$.

ANSWER: (C)