Solve the triangle What is the measure of angle A degree Rou

Solve the triangle. What is the measure of angle A? degree (Round to the nearest tenth as needed.) What is the measure of angle B? degree (Round to the nearest tenth as needed.) What is the measure of angle C? degree (Round to the nearest tenth as needed.)

Solution

a) Angle A : apply cosine rule: a^2 = b^2 +c^2 - 2bccosA

cosA = ( 23^2 +30^2 - 20^2)/2*23*30

A = 41.78 = 41.8 deg

b) Angle B : apply cosine rule: b^2 = a^2 +c^2 - 2accosB

cosB = ( 20^2 +30^2 -23^2)/2*20*30

B =n50.02 = 50.0 deg

c) Angle C = 180 -A -B = 88.2 deg