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In ∆NOP, o =3.6 cm,

User Wcy
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1 Answer

5 votes

First, notice that since the sum of the internal angles of any triangle must always be equal to 180, then:


\begin{gathered} \angle N+\angle O+\angle P=180 \\ \Rightarrow119+5+\angle P=180 \\ \Rightarrow\angle P=180-119-5 \\ \Rightarrow\angle P=56 \end{gathered}

Draw a diagram of the triangle to visualize the situation:

Draw the altitude of the triangle through the vertex N. Let H be the point where the altitude through N intercepts the line OP. From the trigonometric relations, notice the following:


\begin{gathered} \tan (O)=(HN)/(OH) \\ \cos (P)=(HP)/(NP) \\ \sin (P)=(HN)/(NP) \end{gathered}

Substitute the known values:


\begin{gathered} \tan (5)=(h)/(OH) \\ \cos (56)=\frac{HP}{3.6\operatorname{cm}} \\ \sin (56)=\frac{h}{3.6\operatorname{cm}} \end{gathered}

Isolate OH from the first equation, HP from the second and h from the third one:


\begin{gathered} OH=(h)/(\tan (5)) \\ HP=3.6\operatorname{cm}*\cos (56) \\ h=3.6\operatorname{cm}*\sin (56) \end{gathered}

Substitute the expression for h from the third equation into the expression for OH:


OH=\frac{3.6\operatorname{cm}*\sin (56)}{\tan (5)}

Finally, notice that the length of n equals the length of the segment OP, which is the sum of the lengths of the segments OH and HP:


\begin{gathered} n=OH+HP \\ =3.6\operatorname{cm}*(\sin(56))/(\tan(5))+3.6\operatorname{cm}*\cos (56) \\ =34.1134\ldots cm+2.0131\ldots cm \\ =36.1265\ldots cm \end{gathered}

Therefore, to the nearest tenth:


n=36.1\operatorname{cm}

In ∆NOP, o =3.6 cm,-example-1
User Nick Daria
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3.1k points