Question

Given c = 628, b = 480 and C = 55°. The value of a in triangle ABC is

765 and 525

765

525

no solution

Answer 1

draw a diagram



this is a 2 part question

1. Find the size of angle B using the sin rule

sin(55)/628 = sin(B)/480

sinB = 480 sin(55)/628

\[B = \sin^{-1} (480 \times \sin(55))/628\]

use the angle sum of a triangle to find angle A

2. Use the cosine rule to find he length of a

\[a^2 = 628^2 + 480^2 - 2 \times 628 \times 480 \times \cos(A)\]