The length of the diagonal of a Rectangle is 14cm,and it forms a 30 degree angle in one corner of the rectangle.What is the area of the rectangle.(A=LxW)Just number 20

Respuesta :

[tex]\text{Area}=84.87(cm^2)[/tex]

Explanation

Step 1

draw the rectangle

here we have a rigth triangle,then

Let

[tex]\begin{gathered} hypotenuse=14 \\ agle=30\text{ \degree} \\ \text{adjacent side= length= l} \end{gathered}[/tex]

so, we need a function that relates those values

[tex]\cos \Theta=\frac{adjacent\text{ side}}{\text{hypotenuse}}[/tex]

replace and solve for length

[tex]\begin{gathered} \cos \Theta=\frac{adjacent\text{ side}}{\text{hypotenuse}} \\ \text{hypotenuse}\cdot\cos \Theta=adjacent\text{ side} \\ 14\text{ cm }\cdot\cos 30=l \\ 12.12435\text{ cm=l} \end{gathered}[/tex]

Step 2

width

similarity, we need a function that relates

[tex]\sin \text{ }\Theta=\frac{opposite\text{ side}}{\text{hypotenuse}}[/tex]

let

[tex]\text{opposite side= width=w}[/tex]

replace and solve for w

[tex]\begin{gathered} \sin \text{ }\Theta=\frac{opposite\text{ side}}{\text{hypotenuse}} \\ \text{hypotenuse}\cdot\sin \Theta=opposite\text{ side} \\ 14\text{ cm }\cdot\sin \text{ 30=w} \\ 7cm=w \end{gathered}[/tex]

Step 3

finally, the area of a rectangle is given by

[tex]\begin{gathered} \text{Area}=\text{ length }\cdot width \\ \text{replacing} \\ \text{Area}=(12.12\cdot7)(cm^2) \\ \text{Area}=84.87(cm^2) \end{gathered}[/tex]

therefore, the answer is

[tex]\text{Area}=84.87(cm^2)[/tex]

I hope this helps you

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