1) G=140º - angles on a straight line add to 180, H=140º - corresponding angles are congruent
2) set up the equation, since co-interior angles add to 180º the equation should be: x+40+3x+60
add like terms
4x+100=180
subtract 100
4x=80
divide by 4
x=20
3. the angles given are alternate angles meaning they are congruent, set up and equation: 3x-10=7x-42
add like terms
-4x=52
divide by 4
x=-13
To find angle DHG input the answer into the angles equation
7(13)-42
91-42
49
DHG=49º
