Question

Determine the value of x.
Question 11 options:

A)

5

B)

5

C)

10

D)

Answer 1

Answer:   $\frac{10}{\sqrt{3}}$

This is equivalent to $\frac{10\sqrt{3}}{3}$

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Explanation:

To get the first value mentioned above, we simply divide the long leg (10) over the square root of 3.

This is due to the fact that if x is the short leg, then x*sqrt(3) is the long leg. We go in reverse of this process to go from long leg to short leg.

The expression $\frac{10}{\sqrt{3}}$ is the same as $\frac{10\sqrt{3}}{3}$ after we multiply top and bottom by sqrt(3) to rationalize the denominator.

Side notes:

• This entire process only applies to 30-60-90 triangles.
• The hypotenuse of a 30-60-90 triangle is twice as long as the short leg, so the hypotenuse is $2x = 2*\frac{10\sqrt{3}}{3} = \frac{20\sqrt{3}}{3}$  units long.
• You could use the tangent ratio to help isolate x. You would either say tan(30) = x/10 or tan(60) = 10/x as the first equation to set up.