Question #cb86d

1 Answer
Nghi N.
Aug 27, 2015

Find included angle of a triangle knowing: area = 15 cm^2, sides 5 cm and 8 cm.

Explanation:

Use the trig identity: S = 1/2 bc.sin A
S --> Area = 15 ; side b = 5; side c = 8; find sin A
#sin A = (2S)/(bc) = (2(15))/(5(8)) = 30/40 = 3/4 = 0.75#
Calculator --> #A = 48.59# deg or #A = 180 - 48.59 = 131.41# deg

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