2. calculate the measure of angle A. a = 10 C = 7 b = 8 A
The oblique triangle has a given if three sides (SSS). Find the angle A, using the law of cosines (angle version).
- cos A = b² + c² - a² / ²bc
- cos A = 8² + 7² - 10² / 2(8)(7)
- cos A = 64 + 49 - 100 / 2 (8)(7)
- cos A = 13/112
- ∠A = cos -¹ (13/112)
- ∠A = 83.33°
hope this helps :)
