sec 3, #20

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sec 3, #20

by cindyqtran » Mon Oct 29, 2007 6:50 pm
20. In the figure above, line AC represents a seesaw that is touching level ground at point A. If B is the midpoint of AC, how far above the ground is point C?
(1) x = 30
(2) Point B is 5 feet above the ground.

OA is B
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by samirpandeyit62 » Mon Oct 29, 2007 10:05 pm
let AB = a so AC =2a

stmt 1: x =30 degs so the traingle ACO (where O is third vertex fomed when a perpendicuar is dropped from C) is 30 -60 -90 so we can find all sides incl CO but all will be in terms of a INSUFF

stmt 2: let perpendiclaur dropped from B meet the ground at pt L so
we can say that triangles ABL & ACO are similar hence sides are in proportion

so BL/CO = 1/2 (AB/AC)

hence CO =10 SUFF
Regards
Samir