Question

In a triangle, one of the angles measures 70°. If the measure of a second angle is 80°, what is the measure of the remaining angle?

a) 20°
b) 30°
c) 40°
d) 110°

Answer 1

To find the measure of the remaining angle in a triangle with one angle measuring 70° and another 80°, subtract the sum of these angles from 180°, yielding 30° for the third angle.

Step-by-step explanation:

The question is asking for the measure of the remaining angle in a triangle when two angles are already known to be 70° and 80°. According to the Triangle Sum Theorem, the sum of the angles in a triangle is always 180°. Therefore, to find the measure of the third angle, simply subtract the sum of the known angles from 180°.

Here's how to calculate it step-by-step:

1. Add the measures of the two known angles: 70° + 80° = 150°.
2. Subtract the sum from 180° to find the measure of the remaining angle: 180° - 150° = 30°.

So, the measure of the remaining angle is 30°, which corresponds to option (b).