Add up the blue and green first then you - the red which is 12
so 6+9=15 then - from 15 - 12=3

5° is the difference

Step-by-step explanation:

One of the ramps is 5° and the other one is 10°. The difference between these 2 ramps is of 5°.

10 - 5 = 5

And as you can see in the image, the mid ray is what divided both of the other rays, and its right in the middle. Both rays combined gives you 10° as it shows, and half of 10 is 5. So the difference will be of 5°

Hope this helped!

Have a day!