<span>For this question, let's move the decimal number 2 spaces to the right. 2.16-->216 You need 21 ten rods and 6 cubes. Why: I wouldn't do 2 hundred flats because 2 isn't divisible by 3. Put the ten rods into 3 equal group, then do the same with the cubes. You should end up with 7 in each group since 21 divided by 3 is 7. You should also end up with 2 cubes in each group. So in one group you have 72. Now move the decimal back to where it came from, 2 spaces to the left. Now you have 0.72. </span>
For that transformation you just have to use polar coordinates, notice that when you use polar coordinates the radius is constant when the angles varies and the angle is constant when the radius varies. Therefore your transformation would be just