 # Chapter 10: Sine and Cosine Formulae and Their Applications – Exercise 10.1

## Sine and Cosine Formulae and Their Applications – Exercise 10.1 – Q.1

∠A = 45°,∠B = 60° and ∠C = 75°

Using sine rule, ## Sine and Cosine Formulae and Their Applications – Exercise 10.1 – Q.2

∠C = 105°, ∠B = 45°, a = 2

From here we can calculate that

∠A = 30°

a sin B = b sin A

⟹ 2sin 45 = b sin 30 ## Sine and Cosine Formulae and Their Applications – Exercise 10.1 – Q.3

a = 18, b = 24, c = 30, ∠C = 90° ## Sine and Cosine Formulae and Their Applications – Exercise 10.1 – Q.4 Let a = k sin A, b = k sin B (Using sine rule)

LHS ## Sine and Cosine Formulae and Their Applications – Exercise 10.1 – Q.5 Let a = k sin A, B = k sin B, c = k sin C

LHS, ## Sine and Cosine Formulae and Their Applications – Exercise 10.1 – Q.6 LHS, = RHS

## Sine and Cosine Formulae and Their Applications – Exercise 10.1 – Q.7 LHS, = RHS

## Sine and Cosine Formulae and Their Applications – Exercise 10.1 – Q.8 Let a = k sin A, b = k sin B, c = k sin C

LHS, ## Sine and Cosine Formulae and Their Applications – Exercise 10.1 – Q.9 Let a = k sin A, b = k sin B, c = k sin C

RHS, ## Sine and Cosine Formulae and Their Applications – Exercise 10.1 – Q.10 LHS, 