Question

Find the value of 13 years ago

Answer 1

So you need to use the trigonometric formulas for right angled triangles, like sin(angle)=opposite/hypotenuse
cos(angle)=adjacent/hypotenuse
tan(angle)=opposite/adjacent

Have you used these before?

Answer 2

yes i have but only with one angle never two

Answer 3

would you use sin-1,cos-1,tan-1

Answer 4

Sorry, I hope this reply isn't too late.
Yes you use the inverses (:
Work out <F and <G seperately.
Or alternatively, work out one of them and then use the fact that angles in a triangle sum up to 180 degrees. Then for example, <G=180-90-(<F)

Does this help? Again, sorry for the delay!