Law of Sine

Sine Rule

- identify the sine rule

- solve sine rule

- practice exercises

- feedback

Open Ended

How does sine rule differ from other rules in trigonometry?

LET'S TRY

Solve the following

Open Ended

In triangle ABC, A = 67.6 deg, B = 45.5 deg and AB = 7.6cm. Find angle C

Open Ended

In triangle ABC, A = 67.6 deg, B = 45.5 deg and AB = 7.6cm. Find the length of BC

Open Ended

In triangle ABC, A = 67.6 deg, B = 45.5 deg and AB = 7.6cm. Find the length of AC

SOLUTION

In triangle ABC, A = 67.6 deg, B = 45.5 deg and AB = 7.6cm. Find angle C

In triangle ABC, A = 67.6 deg, B = 45.5 deg and AB = 7.6cm. Find the length of BC

In triangle ABC, A = 67.6 deg, B = 45.5 deg and AB = 7.6cm. Find the length of AC

Another example

let's try

Open Ended

In triangle ABC, B = 58.3 deg, C = 39.4 deg and BC = 12.5cm. Find angle A

Open Ended

In triangle ABC, B = 58.3 deg, C = 39.4 deg and BC = 12.5cm. Find length AB

Open Ended

In triangle ABC, B = 58.3 deg, C = 39.4 deg and BC = 12.5cm. Find length AC

SOLUTION

In triangle ABC, B = 58.3 deg, C = 39.4 deg and BC = 12.5cm. Find angle A

In triangle ABC, A = 67.6 deg, B = 45.5 deg and AB = 7.6cm. Find the length of AB

In triangle ABC, A = 67.6 deg, B = 45.5 deg and AB = 7.6cm. Find the length of AC

Open Ended

In triangle ABC, B = 50^o , AB 7.5 cm and AC = 9.5 cm. Find angle C.

Open Ended

In triangle ABC, B = 50^o , AB 7.5 cm and AC = 9.5 cm. Find angle A.

Open Ended

In triangle ABC, B = 50^o , AB 7.5 cm and AC = 9.5 cm. Find length BC.

SOLUTION

In triangle ABC, B = 50^o , AB 7.5 cm and AC = 9.5 cm. Find angle C.

In triangle ABC, B = 50^o , AB 7.5 cm and AC = 9.5 cm. Find angle A.

In triangle ABC, B = 50^o , AB 7.5 cm and AC = 9.5 cm. Find length BC.

let's practice

Multiple Choice

Find b if angle A = 64 deg, B = 98 deg and a = 29 mi

• 32

• 36

• 40

• 41

Multiple Choice

Find b if angle A = 57 deg, c = 35 cm and a = 33 cm

• 31.3

• 34.1

• 42.2

• 45.5

Multiple Choice

Find c if angle C = 90 deg, B = 30 deg and b = 15 in

• 20

• 28

• 30

• 33

Multiple Choice

In triangle RST, R = 153 deg, t= 29km, r=16km. Find angle S.

• 64

• 10

• 2

• not a triangle

Multiple Choice

What is the value of segment KP?

• 16

• 21

• 25

• 31

Multiple Choice

What is the value of segment PH?

• 16

• 21

• 25

• 31

Multiple Choice

What is the value of segment KP?

• 16

• 21

• 25

• 31

Poll

did you understand the sine rule?

• very clear

• need more practice

• no