What is the largest 4- digit number that is divisible by 3, 6, and 9? Explain how you know.

Explanation:

Start with the largest four digit number possible (9999) and see if it's divisible by 3, 6 and 9

When dividing the number over 6, we don't get a whole number. So 6 is not a factor of 9999, and we cross 9999 off the list.

Decrease the number by 9. We do this because the result will be another multiple of 9 (which is automatically also a multiple of 3 as well, since 9 = 3*3)

So we go from 9999 to 9990

Repeat the last set of steps we did earlier

Every result is a whole number, which shows that 9990 is a multiple of 3, 6 and 9. In other words, 9990 is divisible by 3, 6 and 9. It's the largest such 4 digit number.

circle area = pi * radius^2

if diameter = 10 then radius = 5

circle area = pi * 5^2

circle area = pi * 25

circle area = 78.5398163397 square units

step-by-step explanation: