A triangle has 3 interior angles and the sum of its interior angles is 180°. If one of the three interior angles measures 80° and the two remaining angles has the same measure, what is the measure of the 3rd interior angle?

The 3 rd interior angle would have the measure of 50°as the question says that the remaining two interior angles have the congruent magnitude thats why if one of the interior angle is 80° then the remaining angles would be 100° So as the remaining two angles measure the same we can say that the third angle measures 100°/2 = 50°

For proof :

If the remaining two angles be x then the equation forms

x + x + 80° = 180°

=> 2x = (180 - 80)°

=> x = (100/2)°

=> x = 50°

Therefore the value of x = 50°

Hope it helps

answer: the answer is 110