Friday 2/26 - Law of Sines and Law of Cosines

Which one is the easy way to remember trigonometric ratios?

• Sah Coh Toa
• Soh Cah Toa
• Soh Cah Tao
• Soh Ceh Toa

Tags

CCSS.HSG.SRT.C.6

Identify the Law of Sines

• $\sin^2x+\cos^2x=1$

• $\frac{\sin\left(A\right)}{a}=\frac{\sin\left(B\right)}{b}=\frac{\sin\left(C\right)}{c}$

• $\sin\left(A\right)\sin\left(B\right)\sin\left(C\right)=1$

• Soh Cah Toa

Tags

CCSS.HSG.SRT.D.10

CCSS.HSG.SRT.D.11

Which of the following formulas shows the Law of Cosines?

• c² = a² + b² - 4ac + cosA
• c² = a² - b² - 2abcosC
• c² = a² + b² - 2abcosC
• (cos A)/a = (cos B)/b

Tags

CCSS.HSG.SRT.D.10

CCSS.HSG.SRT.D.11

Using the Law of Sines, find the length of side AB.

 $\frac{\sin A}{a}=\frac{\sin B}{b}=\frac{\sin C}{c}$  

• 10

• 8

• 6.1

• 4.9

Tags

CCSS.HSG.SRT.D.10

CCSS.HSG.SRT.D.11

What is the measure of angle A?

(Use the law of Sines)

 $\frac{\sin A}{a}=\frac{\sin B}{b}$  

• 50 degrees

• 60 degrees

• 78 degrees

• 74 degrees

Tags

CCSS.HSG.SRT.D.10

CCSS.HSG.SRT.D.11

Find the length of p

(Use the law of Sines) 

 $\frac{\sin A}{a}=\frac{\sin B}{b}$  

• 14.5

• 15.1

• 15.8

• 16.7

Tags

CCSS.HSG.SRT.D.10

CCSS.HSG.SRT.D.11

Use Law of Cosines to find angle T:

 $a^2=b^2+c^2-2bc\ \cos\ A$  

• 62.2 degrees

• 53.1 degrees

• 59.5 degrees

• 64.7 degrees

Tags

CCSS.HSG.SRT.D.10

CCSS.HSG.SRT.D.11

Use the Law of Cosines to find the value of x. The first step is done for you:

 $a^2=b^2+c^2-2bc\ \cos\ A$ 

Substitute to get:
 $25^2=32^2+37^2-2\left(32\right)\left(37\right)\cos x$  

find x

• 41.7

• 51.7

• 61.7

• 71.7

Tags

CCSS.HSG.SRT.D.10

CCSS.HSG.SRT.D.11

How challenging do you find this topic after yesterday's review?

(Law of Sines and Law of Cosines)

• easy

• a little easy

• not so easy

• difficult

Tags

CCSS.HSG.SRT.D.10

CCSS.HSG.SRT.D.11