Question

In triangle ABC, a = 4, b = 3 and ∠A = 60°. If ' c' is a root of the equation c² – 3c – k = 0. Then k = ______. (with usual notations)

Options

• 6.00

• 7.00

• 8.00

• 9.00

Answer 1

In triangle ABC, a = 4, b = 3 and ∠A = 60°. If ' c' is a root of the equation c² – 3c – k = 0. Then k = 7.00. (with usual notations)

Explanation:

From cosine rule a² = b² + c² – 2bc cos A

16 = 9 + c² – 2.3.c cos 60°

⇒ c² – 3c – 7 = 0