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Each angle on a triangle is connected to two sides and is facing another.

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The longest side of the triangle is always the hypotenuse.

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The other side that makes the angle is called the adjacent.

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The final side not connected in any way to the angle is called the opposite.

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For example, using the image below, you can see which side is denoted by each term from the highlighted angle's perspective.

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One of the ways you can approach this style of question is by using SOHCAHTOA.

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This can be written more visually as

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\\[\\text{S}^\\text{O}_\\text{H}\\space\\text{C}^\\text{A}_\\text{H}\\space\\text{T}^\\text{O}_\\text{A}\\]

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It represents each trigonometric function and what they are equivalent to.

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Written out in full, we would have:

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SIN: opposite / hypotenuse

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COS: adjacent / hypotenuse

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TAN: opposite / adjacent

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For example, $\\sin$ is represented by the first S.

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If we were given an angle, say of $30^\\circ$,

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$\\sin(30^\\circ)=\\frac{\\text{opposite}}{\\text{hypotenuse}}$

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Evaluating $\\sin(30^\\circ)=\\frac{1}{2}$, we now know that $\\frac{\\text{opposite}}{\\text{hypotenuse}}=\\frac{1}{2}$

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If we were given one of these sides, we would then be able to work out the other one by multiplying accordingly.

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Similarly if we were given two sides, and told to work out a specific angle, we could.

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Referring to the image above, suppose we want to find the highlighted angle and we are given that the hypotenuse is equal to $5$ units, and the adjacent is $4$ units.

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We would determine from SOHCAHTOA that we need to use cos since we have the values for A and H.

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So, $\\cos(x)=\\frac{4}{5}$

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Hence, $x=\\cos^{-1}(\\frac{4}{5})=36.87^\\circ$

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$a=\\var{a[0]}$

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$x=\\var{x[0]}^\\circ$

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$c=$ [[0]]

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$b=\\var{a[1]}$

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$y=\\var{x[1]}^\\circ$

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$b=\\var{a[3]}$

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$x=\\var{x[3]}^\\circ$

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$x=\\var{x[4]}^\\circ$

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$a=\\var{fh}$

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$c=\\var{fa}$

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$x=$ [[0]]$^\\circ$

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Using the triangle pictured below (not to scale), find the specified side lengths using trigonometry and the given values.

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Give your answer to two decimal places.

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Finding lengths of sides of triangles

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