How to work out an exterior angle

What are the soultion(s) to the quadratic equation 40- x^2=0

In the diagram, the ratios of two pairs of corresponding sides are equal to prove that almn - axyz by the sas similarity theorem, it also needs to be shown that x 6 z un z zz un = 2x zləzz lezy

8. kelly wants to buy a magazine that is $25. later the magazine was marked up an additional 20%. what is the new price?