Answer:
a ≈ 4.9
Step-by-step explanation:
using the Cosine Rule in Δ ABC
a² = b² + c² - (2bc cosA )
= 16² + 18² - (2 × 16 × 18 × cos15° )
= 256 + 324 - (576cos15° )
= 580 - 576cos15
= 23.6267 ( take square root of both sides )
a = [tex]\sqrt{23.6267}[/tex]
≈ 4.9 ( to the nearest tenth )
