Expert: Paul Klarreich - 1/24/2008

Question
Find each measure using the given measures. Round to the nearest tenth.

Q1: Find f if g = 15, h = 13, and m F = 48.

Q2: Find h if f = 13.7, g = 16.8, and m H = 71.

Answer
Questioner:   Kimberly
Category:  Advanced Math
Private:  No
 
Subject:  trigonometry
Question:  Find each measure using the given measures. Round to the nearest tenth.

Q1: Find f if g = 15, h = 13, and m F = 48.

Q2: Find h if f = 13.7, g = 16.8, and m H = 71.
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Q1: Find f if g = 15, h = 13, and m F = 48.

I assume you are talking about triangle FGH, and in that case, you will write the Law of Cosines.  

How can you tell?  If you are GIVEN information of this type:

A.S.A. (angle-side-angle) : use Law of Sines.
s.A.A : use Law of Sines.
S.S.A : use Law of Sines, but be careful.
S.S.S.: use Law of Cosines.
S.a.S.: use Law of Cosines.  << THAT'S IT, HERE.


f^2 = g^2 + h^2 - 2gh cos F

f^2 = (15)^2 + (13)^2 - 2(15)(13) cos 48

f^2 = 225 + 169 - 390 cos 48

Now use your calculator.

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Q2: Find h if f = 13.7, g = 16.8, and m H = 71.

Same thing:

h^2 = f^2 + g^2 - 2fg cos H

Use your calculator with a vengeance now.