Find the number to complete the proportion
5 to 3 = blank to 6

We multiply 6 by a scale factor of 

So the answer is 10, 

This can also be seen because:

= 

So 5:3 is like 5/3

x:6 or x/6

we know if we multiply 2 equal fractions by each other, but one is flipped, we will get one exg
1/4=2/8
1/4 times 8/2=8/8=1

so since 5/3=x/6
5/3 times 6/x=1
5/3 times 6/x=30/3x=1
30/3x=1
multiply both sdies by 3x to cancel out the fraction
30=3x
divide both sdies by 3
10=x

the answer is 10:6

We’re gonna need a picture to refer to in order to figure it out. try reposting your question with the picture included.