Unformatted text preview: Area = K = 1 2 bc sin A (2.23) The above formula for the area of △ ABC is in terms of the known parts A , b , and c . Similar arguments for the angles B and C give us: Area = K = 1 2 ac sin B Area = K = 1 2 ab sin C (2.24) (2.25) Notice that the height h does not appear explicitly in these formulas, although it is implicitly there. These formulas have the advantage of being in terms of parts of the triangle, without having to ±nd h separately. Example 2.13 b = 5 a c = 7 A = 33 ◦ B C Find the area of the triangle △ ABC given A = 33 ◦ , b = 5, and c = 7. Solution: Using formula (2.23), the area K is given by: K = 1 2 bc sin A = 1 2 (5)(7) sin 33 ◦ K = 9.53...
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 Fall '11
 Dr.Cheun
 Calculus, Geometry, Trigonometry, Angles, Congruence, Formulas, Hypotenuse

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