PLEASE HELP ME FIGURE OUT HOW THE ANGLES EQUAL 180 DEGREES...?

Question

anonymous · Answer

the sum of the measures of angle 1 and angle 2 is equal to 180°. I cant figure out how.

espex · Answer

Any time parallel lines are bisected by another line, the opposing angles are equal. Basically this means that the angles "kitty-corner" from each other measure the same. Looking at the top line it should be clear that the horizontal line measures 180 degrees. So the angle on the left plus the angle on the right equal 180.
Since opposing angles are equal, the angle on the right is the same measurement as angle 2 and the angle on the left is the same measurement of angle 3. Since the two lines are parallel, then the angle on the "top" left is the same as angle 1, and so:
"top left" + "top right" = 180,
"top left" = ang1,
"top right" = ang2,
thus ang1 + ang2 = 180.

Clear as mud? :)

anonymous · Answer

Wow. That helps so much. Thanks :)