Answer:
6.37 units
Explanation:
In this case the x side is the OPPOSITE side and the 15 is the ADJACENT side (adjacent means next to) so the trig function that puts together OPP and ADJ is the tangent function.
tan 23° = OPP/ADJ
tan 23° = x/15
Multiply both sides by 15
15tan23° = x
You should really be able to type that entire 15tan23° into your calculator all at once. If not, do tan23° [enter] and then times by 15.
Either way 6.37, this is a side length so throw some units on there if you know them (but its definitely NOT degrees, bc it's a side)