
Brandon R. answered 06/14/20
Bachelors Degree in Secondary Mathematics
Hello, let's review the meaning of supplementary angles. They are angles that add up to a total of 180 degrees. We know that the two angles must equal 180 degrees, and must also have a ratio of 2:7. Let's think about this using some basic algebra.
The ratio 2:7 can be applied extended to represent 2x:7x for any number x. See below:
x = 2; 4:14
x=5; 10:35
These examples follow the 2:7 ratio. We want to find the ratio 2x : 7x that allows us to add the two numbers and get 180. We can set up an algebraic equation to do this:
2x + 7x = 180 <-- solve for x. Start by combining like terms.
9x = 180 <-- divide both sides by 9
x = 20.
What are our two angles when x = 20?
2 (20) = 40
7 (20) = 140
CHECK:
40+140 = 180 correct
Do 40 and 140 follow the given ratio? Yes!