Outcomes in a sample space :)
supplementary angles add up to 180°.
x = measure of such angle
x + 20 = measure of her sibling.
since "x" has 20 less than her sibling, then clearly her sibling has to have 20 more than "x".


The equation of a elipse:

The length of the major axis is equal 2a if a > b or 2b if b > a.
We have

therefore the length of the major axis is equal 2 · 7 = 14.
39 it's an arithmetic sequence in which the common difference is +7
112.5 I believe is the right answer