Answer:
G. ABD = 74
H. DBC = 206
I. XYW = 33.75
J. WYZ = 46.25
Explanation:
For G and H: You have a straight line (ABC) with another line coming off of it, creating two angles (ABD and DBC). A straight line has an angle of 180 degrees. This means that the two angles from the straight line when combined will give you 180 degrees. Solve for x.
ABD + DBC = ABC
(1/2x + 20) + (2x - 10) = 180
1/2x + 20 + 2x - 10 = 180
5/2x + 10 = 180
5/2x = 170
x = 108
Now that you have x, you can solve for each angle.
ABD = 1/2x + 20
ABD = 1/2(108) + 20
ABD = 54 + 20
ABD = 74
DBC = 2x - 10
DBC = 2(108) - 10
DBC = 216 - 10
DBC = 206
For I and J: For these problems, you use the same concept as before. You have a right angle (XYZ) that has within it two other angles (XYW and WYZ). A right angle has 90 degrees. Combine the two unknown angles and set it equal to the right angle. Solve for x.
XYW + WYZ = XYZ
(1 1/4x - 10) + (3/4x + 20) = 90
1 1/4x - 10 + 3/4x + 20 = 90
2x + 20 = 90
2x = 70
x = 35
Plug x into the angle values and solve.
XYW = 1 1/4x - 10
XYW = 1 1/4(35) - 10
XYW = 43.75 - 10
XYW = 33.75
WYZ = 3/4x + 20
WYZ = 3/4(35) + 20
WYZ = 26.25 + 20
WYZ = 46.25