Transversal t cuts parallel lines a and b as shown in the diagram. which equation is necessarily true? a. m∠1 = m∠2 b. m∠4 = m∠6 c. m∠1 + m∠5 = 90° d. m∠3 + m∠5 = 180° e. m∠7 = m∠8

Option D; m∠3 + m∠5 = 180°

This is about angle theorems.

Option A: m∠1 = m∠2. This is not true because sum of angles on a straight line is 180° and the line that divides this 2 angles is not perpendicular to the straight horizontal line to bisect it equally. Option B: m∠4 = m∠6; This statement is not true because though their sum is 180° but again they are transverse angles which are not equal from the line that forms them. Option C: m∠1 + m∠5 = 90°; This is not correct because m∠1 = m∠5 and the line that forms each of them is not a 45° angleOption D; m∠3 + m∠5 = 180°. This is true because from angle from the same side of the transversal theorem, they must add up to 180°.Option E; m∠7 = m∠8. Same reason as in option A, the statement is not true

That means only option D is true.

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