Free Printable Law of Cosines

1.

Which of the following formulas shows the Law of Cosines?

a)

c² = a² + b² - 4ac + cosA

b)

c² = a² - b² - 2abcosC

c)

c² = a² + b² - 2abcosC

d)

(cos A)/a = (cos B)/b

2.

What are the possible criteria for the Law of Cosines?

a)

SSA, SSS

b)

SSA, ASA

c)

SSS, SAS

d)

AAS, ASA

3.

Which law would you use?

a)

Law of Sines

b)

Law of Cosines

4.

Which law would you use?

a)

Law of Sines

b)

Law of Cosines

5.

What is the correct set up to find angle H?

a)

$\cos\ H\ =\ \frac{11^2-13^2-15^2}{4\left(11\right)\left(15\right)}$

b)

$\cos\ H\ =\ \frac{11^2+13^2+15^2}{2\left(13\right)\left(15\right)}$

c)

$\cos\ H\ =\ \frac{11^2-13^2-15^2}{-2\left(13\right)\left(15\right)}$

d)

$H^2\ =\ 11^2+13^2+15^2-2\left(13\right)\left(15\right)\cos11$

6.

$m=$

a)

12.7

b)

13.1

c)

13.6

d)

14.2

7.

$m\angle G=$

a)

$74.3\degree$

b)

$76.1\degree$

c)

$76.9\degree$

d)

$77.5\degree$

8.

What is the correct set up to find side p?

a)

$p^2=16^2+19^2-2\left(16\right)\left(19\right)\cos48$

b)

$p^2=16^2-19^2+2\left(16\right)\left(19\right)\sin48$

c)

$p^{ }=16^{ }+19^{ }+2\left(16\right)\left(19\right)\cos48$

d)

$16^2=p^2+19^2-5\left(16\right)\left(19\right)\cos48$

9.

Which would you use to find a missing angle?

a)

$\cos\ A\ =\ \frac{b^2-a^2-c^2}{2ba}$

b)

$\cos\ A\ =\ \frac{a^2-b^2-c^2}{-2bc}$

c)

$\cos\ A\ =\ \frac{a^2-b^2-a^2}{4ba}$

d)

$\sin\ A\ =\ \frac{a^2-b^2-c^2}{2bc}$

10.

If $\cos\ A\ =\ 0.345$ how would I find A?

a)

$\cos^{-1}\left(0.345\right)$

b)

$\sin^{-1}\left(0.345\right)$

c)

$\tan\left(0.345\right)$

d)

$180-0.345$

Law of Cosines

Total questions: 10

Worksheet time: 36mins

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