Final answer:
To write the proportion 9:36 = 10:40 using words, you should say '9 is to 10 as 36 is to 40.'
Step-by-step explanation:
The correct way to write the proportion 9:36 = 10:40 using words is option 3) 9 is to 10 as 36 is to 40.
In this proportion, the first ratio compares the numbers 9 and 10, and the second ratio compares the numbers 36 and 40.
By setting the two ratios equal to each other, you are stating that the relationship between 9 and 36 is the same as the relationship between 10 and 40.