To write 86.6 as a fraction you have to write 86.6 as numerator and put 1 as the denominator. Now you multiply numerator and denominator by 10 as long as you get in numerator the whole number.
86.6 = 86.6/1 = 866/10
And finally we have:
86.6 as a fraction equals 866/10
I GOT IT FROM GOOGLE