Question

Line m is intersected by line t , as shown in the diagram below. Based on the diagram, which of the following equations must be true? A m∠1+m∠2=180°
B m∠1+m∠3=180°
C m∠2+m∠3=90°
D m∠2+m∠4=90°

Answer 1

the answer is quite simple on this one. angles 1 and 3 are equal, and angles 2 and 4 are equal.

if you thi k about moving line t then you can see 2 and 4 will not add to 90°. angles 2 and 3 do not add to 90° because their angles added make a straight line (180°). answer B is almost true but not quite since the angles are not perpendicular to each other (1 and 3).

therefore, answer is A because of said explanation about answer B in previous paragraph. they make a straight line (180°). just basic geometry.