These are all basically the same type question involving trig ratios
remember S-O-H-C-A-T-O-A
which stands for, in right triangles.
sin = opposite side / hypotenuse
cosine = adjacent / hypotenuse
tangent = opposite side/adjacent side
Let's do the first one...then you try the rest....
Looking for angle A Opposite side is 4 hypotenuse is 5
SO the sin of angle A = opposite/hypotenuse = 4/5
sin A = 4/5
then use your calculator to use 'ARCSIN' (also called sin inverse) of 4/5
arcsin (4/5) = 53.13 degrees
You could also use cosine or tangent to find angle A
cos A = adjacent/hypotenuse = 3/5 ARCOS (3/5) = 53.13 degrees
....or use the tangent
tangent = opposite/adjacent = 4/3 arctan (4/3) = 53.13 degrees
Now YOU try the others ! Good Luck ! 
