Hi Mr. G, I didn’t understand 10b or c, since multiplying cos 112.5 degrees results in a relative obtuse angle of 135 degrees, but from the 135 you can get a RAA if 45 degrees (but I’m not sure if that’s allowed). Also, did c) I think we have to use the quadratic formula, but I don’t know what values to sub in

To see this working, head to your live site.

QUESTION (b)

QUESTION (c)

Also, Question #7 of the practice test from the website is the exact same question as (c) (I'm pretty sure) but in radians. Here's the answer from that one: