2.
The 21 degree angle shown is a corresponding angle to angle 3, which means they are identical, so angle 3 is 21 degrees.
Angle 3 and 4 are supplementary angles which need to add up to 180 degrees.
Angle 4 = 180 - 21 = 159 degrees.
3. A bisector means both sides are the same length.
Set the two equations to equal to solve for x:
4x+12 = 2x +18
Subtract 2x from both sides:
2x +12 = 18
Subtract 12 from both sides:
2x = 6
Divide both sides by 2:
x = 3
Now you have x, solve both equations and add them together:
4(3) +12 = 12+12 = 24
2(3) +18 = 6+18 = 24
24 +24 = 48
AB = 48
