Help in Solution and also Explanation

Question

In ∆ACS, AC = 12, SA = 8 and SC = 16. Determine the measures of all the interior angles of the triangle.

Answer 1

By cosine law cosA = 12² + 8² - 16²)/(2·8·12) = - 0.25; so, A = cos^-1(- 0.25) = 104.4775°;

sinA/16 = sinC/8; sinC = 8sin104.4775°/16; C = sin^-1(sin104.4775°/2) = 28.9550°;

S = 180°- (A + C) = 46.5675°°