math
posted by Anonymous .
The sum of three numbers is 81 and their ratio is 3:7:17. What is the value of the smallest number?

Add up the ratios 3:7:17 to get 27.
Since ratios can be scaled, we can scale the ratios to have a sum of 81 by multiplying the ratios by 3,i.e.
3:7:17 ≡ 9:21:51.
Can you take it from here? 
no i need the answer please

Try to add up the three numbers 9,21 and 51 and see what you get.
You're welcome to confirm your answer if you are not sure.