The measure of
angle A = 76.9
angle B = 50.3°
angle C = 62.8°
We use cosine and sine rule to get the measure of A , B and C
sine rule states mathematically that;
a² = c² + b² + 2bc cosA
23.5² = 15.6² + 14.4²+ 2 × 15.6 × 14.4cos A
552.25 = 450.72 + 449.28cosA
552.25 - 450.72 = 449.28cosA
cosA = 101.53/449.28
cosA = 0.226
A = 76.9°
Using sine rule
a/sin A = b/sinB
23.5/sin 76.9 = 15.6/sinB
23.5 sinB = 15.19
sinB = 15.19/23.5
sinB = 0.646
B = 40.3°
C = 180 - ( 40.3 + 76.9)
C = 180 - 117.2
C = 62.8°