Two intersecting lines create four angles with the same vertex, labeled A , B , C , and D . Angle B is adjacent to ∠A and ∠C . Find m∠A if m∠C=75° .(1 point)

75°

15°

105°

180°

3 answers

Since angle B is adjacent to both angle A and angle C, we can add the measures of angle A and angle C together to find the measure of angle B.

m∠B = m∠A + m∠C

Since m∠C = 75°, we can substitute this value into the equation.

m∠B = m∠A + 75

Since the sum of all angles at a vertex is 180°, we can write another equation.

m∠A + m∠B + m∠C + m∠D = 180

We can substitute the value of m∠C and simplify the equation.

m∠A + m∠B + 75 + m∠D = 180

We are given that the four angles all have the same vertex, so m∠A = m∠B, and m∠C = m∠D.

Substituting these values into the equation, we get:

2m∠A + 75 + 2m∠A = 180

4m∠A + 75 = 180

Subtracting 75 from both sides:

4m∠A = 105

Dividing both sides by 4:

m∠A = 26.25°

So the measure of angle A is 26.25°.

None of the given answer choices are correct, so it seems there may be a mistake in the question or the solutions provided.
wrong
Apologies for the mistake. Let's reevaluate the problem.

Since angles A, B, C, and D are all formed by two intersecting lines, we know that angle A and angle C are vertical angles. Vertical angles are congruent, meaning they have the same measure.

Given that m∠C = 75°, we can conclude that m∠A = 75° as well.

Therefore, the correct answer is:

m∠A = 75°.