Part G
The two angles ABD and DBC form a straight line, so the angles add to 180 degrees.
Let's solve for x.
angle ABD + angle DBC = 180
(0.5x+20) + (2x-10) = 180
2.5x+10 = 180
2.5x = 180-10
2.5x = 170
x = 170/2.5
x = 68
Then we'll use this to find angle ABD
angle ABD = 0.5*x + 20
angle ABD = 0.5*68 + 20
angle ABD = 34 + 20
angle ABD = 54
Answer: 54 degrees
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Part H
Use the value of x we found back in part G to find the measure of angle DBC
angle DBC = 2x - 10
angle DBC = 2(68) - 10
angle DBC = 136 - 10
angle DBC = 126
An alternative is to subtract the measure of angle ABD from 180
angle ABD + angle DBC = 180
angle DBC = 180 - (angle ABD)
angle DBC = 180 - 54
angle DBC = 126
Answer: 126 degrees
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Part I
This time, the two angles add to 90 degrees as shown by the square corner marker.
(angle XYW) + (angle WYZ) = 90
(1.25x - 10) + (0.75x + 20) = 90
2x + 10 = 90
2x = 90-10
2x = 80
x = 80/2
x = 40
which then leads to,
angle XYW = 1.25*x - 10
angle XYW = 1.25*40 - 10
angle XYW = 50 - 10
angle XYW = 40
Answer: 40 degrees
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Part J
We can subtract the result of part I from 90 degrees to get the answer
angle WYZ = 90 - (angle XYW)
angle WYZ = 90 - 40
angle WYZ = 50
Or we could plug the x value x = 40 into the expression for angle WYZ
angle WYZ = 0.75*x + 20
angle WYZ = 0.75*40 + 20
angle WYZ = 30 + 20
angle WYZ = 50
Answer: 50 degrees
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Summary:
The answers we found were
- G. 54 degrees
- H. 126 degrees
- I. 40 degrees
- J. 50 degrees