Answer:
x = 5.34
Step-by-step explanation:
The reference angle is 24 degrees. I'm sure you are aware from the square at the other base angle that is a right triangle. Right triangles have ratios by which we can determine missing side and angle measures. The sin of a reference angle has a ratio that is side opposite/hypotenuse. The cos of a reference angle has a ratio that is side adjacent/hypotenyse. The tan of a reference angle has a ratio that is side opposite/side adjacent.
We need to decide which of these fits our needs according to the angle and sides we are given and need to find. We have the reference angle as 24 degrees, we have the side adjacent to this angle as 12. We are looking for x, which is the side opposite the reference angle. Looking to what our definitions are for each ratio, the sides opposite and adjacent are defining the tan of the reference angle. Setting up the ratio then looks like this:
Multiply both sides by 12 to get
12 tan(24) = x
Do this on your calculator in DEGREE mode to get that
x = 5.342744224
Not sure what your teacher has you round to, but I usually have my students give me 2 decimal places