Question

What is the answer ? A. B. C. or D?

Answer 1

By definition, a Right triangle is a triangle that has an angle that measures 90 degrees (which also called "Right angle").

For this case, you can identify that the triangle given in the exercise is a Right triangle.

To find the measure of the missing angle, you need to use Arccosine function, which is the inverse of the cosine function:

`\alpha=\cos ^(-1)((a)/(h))`

Where "α (alpha)" is the angle you must find, "a" is the adjacent side and "h" is the hypotenuse.

You can set up that, for this case:

`\begin{gathered} a=11 \\ h=23 \end{gathered}`

Then, substituting values and evaluating, you get that the measure of the angle is:

`\begin{gathered} \alpha=\cos ^(-1)((11)/(23)) \\ \alpha=61.42\degree \end{gathered}`

Rounding the answer to nearest whole degree, you get:

`\alpha\approx61\degree`

The answer is: Option C.