The area of a triangle is 2. Two of the side lengths are 2.1 and 3.8 and the includedangle is acute. Find the measure of the included angle, to the nearest tenth of adegree.

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ANSWER

[tex]C=30.1\degree[/tex]

EXPLANATION

The area of a triangle using two given sides and the included angle is given as:

[tex]A=\frac{1}{2}a\cdot b\cdot\sin C[/tex]

where a and b are the sides and C is the included angle.

Therefore, we have to find C given that:

[tex]\begin{gathered} A=2 \\ a=2.1 \\ b=3.8 \end{gathered}[/tex]

Therefore, we have that:

[tex]\begin{gathered} 2=\frac{1}{2}\cdot2.1\cdot3.8\cdot\sin C \\ \Rightarrow\sin C=\frac{2\cdot2}{2.1\cdot3.8}=0.5012 \\ \Rightarrow C=\sin ^{-1}(0.5013) \\ C=30.1\degree \end{gathered}[/tex]

That is the measure of the included angle.