Answer:
a = 7
Explanation:
a² = b² + c² - 2bc × cos α
a² = 2² + ( 5√3 )² - 2 × 2 × 5√3 ×
a² = 49
Using the Cosine rule in the triangle
a² = b² + c² - (2bc cosA )
= 2² + (5 )² - (2 × 2 × 5 × cos30° )
= 4 + 75 - (20 × ) ← exact value of cos30°
= 79 - ( 10 × 3)
= 79 - 30
= 49 ( take square root of both sides )
a = = 7
3.4m questions
4.3m answers
)² - (2 × 2 × 5 × cos30° ) × 
) ← exact value of cos30°
= 7