Because someone else already answer 11 and 12, I will answer 10 :)
Supplementary means the 2 angles add up to 180 degrees. We also know that we want the angles to have a 5:4 ratio. We can set up the following:
5x+4x=180 (X represents the rate the angles increase)
9x = 180
X = 20
Now we can plug in to find the larger angle.
5(20) = Larger angle
100 degrees = Larger Angle
You can double check by plugging in the smaller angle as well and seeing if it adds to 180.
4(20) = Smaller Angle
80 = Smaller Angle.
Both Angles:
100+80= 180
So it checks out :)
I hope this helps you understand!
