How to do geometry??

Question

If one of the four angles formed by two intersecting lines is a right angle, then each of the four angles is a right angle.

Please help me...Thanks!

Answer 1

The 2 lines look like this:  +  

So if one angle is a right angle, then they all have to be right angles otherwise it is impossible.

Answer 2

Two adjacent angles will form a linear pair. They are supplementary, if one is a right angle, then so it the adjacent angle. This would be true for the two adjacent angles on either side of the given right angle. Since vertical angles are congruent, the other angle is also right.

Answer 3

If one of the four angles formed by two intersecting lines is a right angle, then each of the four angles is a right angle; provided the intersecting lines must be STRAIT LINES.