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If isosceles triangle ABC has a 130° angle at vertex B, which statement must be true?

a.m∠A = 15° and m∠C = 35°
b.m∠A + m∠B = 155°
c.m∠A + m∠C = 60°
d.m∠A = 20° and m∠C = 30°.

2 Answers

4 votes

Answer:

b. m∠A + m∠B = 155°

Step-by-step explanation:

Correct on test

User Dirn
by
7.6k points
7 votes

Final answer:

The correct sum of the measures of angles A and C in an isosceles triangle with a 130° angle at vertex B is 50°, with both angles A and C being 25° each. None of the provided options correctly reflect the angle measures based on the sum of the angles in a triangle.

Step-by-step explanation:

If an isosceles triangle ABC has a 130° angle at vertex B, we can determine the measures of the other angles with the understanding that the sum of the angles in any triangle is 180°. Since ABC is isosceles, it has at least two equal angles. However, since the angle at B is already 130°, the equal angles must be at vertices A and C. This leaves 180° - 130° = 50° to be divided equally between angle A and angle C, which means they are each 25°.

Therefore, the correct statement must be that m∠A + m∠C = 50°, which is not one of the provided options. However, based on the logic applied, none of the options are correct since each angle at A and C is 25°, which means they don't align with any of the given choices.

User Duc Manh Nguyen
by
8.8k points
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