Sine Rule and Cosine Rule Clicker Practice SOHCAHTOA

Sine Rule and Cosine Rule Clicker Practice

SOH/CAH/TOA can only be used for right-angled triangles. The Sine Rule can be used for any triangle: C b The sides are labelled to match their opposite angles A The Sine Rule: a = sin. A a B c b = sin. B c sin. C

We use the Sine Rule when: We have two angles and a side OR We have two sides and the non-included angle (this is the ambiguous case)

Practice Together: find the length of h in mm. G Degree mode!! H 76º 26 mm I 41º

Find the length of a in cm. B 53º A 3 sig figs!! 62º 5 c u m u C 5. 53 0

Find the length of f in cm. 3 sig figs!! F m c 13 D 28º u 130º E u 6. 36 0

Practice Together: Find the measure of angle ABC. C 5 cm 47º θ A 6 cm B

Find the measure of angle PRQ: Q 6 km P 27º 3. 5 km θ 3 sig figs!! u R u 51. 1 0. 1

Find the measure of angle EDF: D θ 70º F 9. 5 m 3 sig figs!! 8 m u E u 57. 7 0

We use the Cosine Rule when: Two sides and the INCLUDED angle (SAS) OR All three sides (SSS)

The Cosine Rule A c b B B C a C (One side)2 = (other side)2+(last side)2 2(other side)(last side)cos(angle of 1 st side)

Practice Together: Find the length of side a

Find the length of side r in km: 3 sig figs!! u u 3. 38 0

Find the length of AC in cm: B 8. 3 3 sig figs!! 72º 5. 4 cm A cm u u C 8. 39 0

Practice Together: Find the measure of the unknown angles

Find the measure of angle GHI G 3 sig figs!! 13 H 12 cm I 11 cm cm θ 68. 7 0

Find the measure of angle DEF: 3 sig figs!! F m 5 c m c 10 D 7 cm E 112 0

Find the measure of the largest angle of a triangle with sides 11 cm, 13 cm, and 19 cm. 3 sig figs!! u u 104 0