Question

Find angle "a" in the taper shown. ro

Answer 1

Assume symmetry.
Then 
length of opposite side of angle a, L=((4.265-2.84)/2) =>
sin(a)=L/8.53
=((4.265-2.84)/2)/8.53
=0.08353
=>
a=asin(0.08353)
=4.79 degrees