We know that 12 equals one dozen. It is not asking for a dozen, but for 9 dozen. So, we need to multiply 9 by 12. 9*12 = 108.
It says the rolls of first aid tape were divided equally into 4 boxes. We need to divide these 108 rolls into 4 equal groups, since that is what took place in the problem. So, we divide 108 by 4.
108/4 = 27. There are 27 rolls in each box.
The answer is 145 divided by tan 65 degrees.
Since the equation for tangent is opposite/adjacent, you can just plug the numbers in.
tan(65)=145/x (x being the height that you are trying to find)
tan(65) * x = 145
Then divide tan(65) to isolate the x and you get:
145/tan(65)
Hope this helps!