Answer is 6 3/8 or 6.375
Step by step
You can do this a couple ways.
3/4 = .75 as a decimal
8 1/2 = 8.5 as a decimal
Multiply and you get 6.375
If you want to multiply fractions, change 8 1/2 to a mixed improper fraction and multiply across.
3/4 x 17/2 = 51/8
Simplify 51/8 by division
51 divided by 8 = 6 3/8
Problem solved