How do you solve a triangle if you are given C = 15 degrees, a = 6.25, b = 2.15?

May 13, 2015

To begin with, side c can be calculated using the cosine formula, cos C= $\frac{{a}^{2} + {b}^{2} - {c}^{2}}{2 a b}$

cos 15= (6.25^2 +2.15^2 -c^2)/(2(6.25)(2.15)

c= 4.2101951. Having got side c, get Angle B using the cosine rule again cosB=$\frac{{a}^{2} + {c}^{2} - {b}^{2}}{2 a c}$

= (6.25^2 + 4.2101951^2 - 2.15^2)/(2(6.25)(4.2101951)

B= 7.59499.

Angle A would be !80-B-C= 157.404500