Answer:
1. tan
2. standard
3. y=16.8
Explanation:
1. Trigonometic functions are:
sinA=opposite/hypoteneuse
cosA=adjacent/hypoteneuse
tanA=opposite/adjacent.
We have the opposite side (20) and the adjacent side (y), but not the hypoteneuse, ao we have to use tan.
2.Inverse is only used when we dont know the angle measure, so we use standard.
3.tanA=opp/adj
tan50=20/y
1.19175359259=20/y
y=16.7819926235 or 16.8