CP=12, CM=20. CP is the altitude of the triangle. ACP is a right triangle, so you can solve for CP using Pythagorean's theorem. CP=\sqrt(AC^2-CP^2)=\sqrt(15^2-9^2)=12. AM=AP+PM=9+16=25. Triangle ACM is another right triangle, and CM=\sqrt(AM^2-AC^2)=\sqrt(25^2-15^2)=20.
-9u + 3u = 9 + 9
-6u = 18
u = -18/6
u = -3
Thus, u is equal to -3
If the CPI for 1989 was 124, the rate of the inflation between the base period and 1989 was 24%!
