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3 votes
Please check!!!! I've posted this already but no one is answering so I'm posting for more points.

Please check!!!! I've posted this already but no one is answering so I'm posting for-example-1

2 Answers

2 votes

By the law of sines,


\frac{\sin m\angle A}a=\frac{\sin m\angle B}b\implies\sin m\angle B=(33.7\sin75^\circ)/(51.2)

We get one solution by taking the inverse sine:


m\angle B=\sin^(-1)(33.7\sin75^\circ)/(51.2)\approx39^\circ

In this case there is no other solution!

To check: suppose there was. The other solution is obtained by recalling that
\sin(180-x)^\circ=\sin x^\circ for all
x, so that


180^\circ-m\angle B=\sin^(-1)(33.7\sin75^\circ)/(51.2)\implies m\angle B\approx141^\circ

But remember that the angles in any triangle must sum to 180 degrees in measure. This second "solution" violates this rule, since two of the known angles exceed 180: 75 + 141 = 216 > 180. So you're done.

User SortingHat
by
5.4k points
5 votes

This triangle is not a right triangle. How do we solve this then? You will use the law of sine with is shown below:


(sin A)/(a) =(sin B)/(b) = (sinC)/(c)

What we know is shown in the image attached below:

Plug what you know into the law of sine


(sin75)/(51.2) =(sinB)/(33.7)

To solve for sinB cross multiply

sin75*33.7 = sinB * 51.2

32.55 = sinB*51.2

Divide 51.2 to both sides to isolate sinB

32.55 / 51.2 = sinB / 51.2

0.63577 = sinB

To find B you must use arcsin:


sin^(-1) 0.63577

39.477

^^^This is your rough estimate but you can simply keep it to 39 degrees

This means that your answer is correct!

Hope this helped!

Please check!!!! I've posted this already but no one is answering so I'm posting for-example-1
User CRichter
by
5.6k points