OBLIQUE TRIANGLES

Which law would you need to solve the given problem?

• Law of Sines

• Law of Cosines

• Both

• Neither

To solve triangle ABC, where a = 5, b = 6, c = 7. Which of the following would you need to use first?

• Law of Sines

• Law of Cosines

• Pythagorean Theorem

• None of the above

Find the value of side AB.

• 27.99 units

• 21.74 units

• 18.84 units

• 13.59 units

If C = 135°, a = 52, and A = 30°, what is the value of c?

• 52

• $52\sqrt{2}$

• $\frac{52\sqrt{6}}{3}$

• $26\sqrt{3}$
  

Which of the following would you use to find the length of AC using Sine Rule?

• $\frac{\sin\ 51.3}{81\degree}=\frac{\sin\ AC}{85\degree}$

• $\frac{51.3}{\sin\ 81\degree}=\frac{\sin\ 85\degree}{AC}$

• $\frac{51.3}{\sin\ 81\degree}=\frac{AC}{\sin\ 85\degree}$

• $\frac{51.3}{\sin\ 85\degree}=\frac{AC}{\sin\ 81\degree}$

Which of the following is the correct formula to find the measure of angle A?

•  $\cos^{-1}\ \frac{a^2+b^2-c^2}{2ab}$  

•  $\cos^{-1}\ \frac{b^2+c^2-a^2}{2bc}$ 

•  $\cos^{-1}\ \frac{a^2+b^2-c^2}{2ab}$ 

•  $\cos^{-1}\ \frac{a^2+c^2-b^2}{2ac}$ 

What is the length of PR?

• $PR^2=9.2+8.5-\left(9.2\right)\left(8.5\right)\cos\ 89\degree$

• $PR^2=9.2^2+8.5^2-\left(9.2\right)^2\left(8.5\right)^2\cos\ 89\degree$

• $PR^2=9.2^2+8.5^2-2\left(9.2\right)\left(8.5\right)\cos\ 89\degree$

• $PR^2=9.2^2+8.5^2+2\left(9.2\right)\left(8.5\right)\cos\ 89\degree$

Solve for the measure of angle A if a = 15, b = 21 and c = 28.

• $100.8\degree$

• $47.45\degree$

• $31.75\degree$

• $27.02\degree$

Two sides of a parallelogram are 8 meters and 5 meters, and one of the angles is

 $60\degree$  . What is the length of the shorter diagonal?

If two sides of a triangle are 25 cm and 42 cm and the angle opposite the shorter side is

 $28\degree$  . What is the other parts of the triangle? Give your answer to the nearest whole number.