I prefer to use compatible numbers because by using this method it is easier to make a sum mentally. This is true because compatible numbers are close in value to the actual numbers. For a better understanding, let's take an example:
Suppose you have two numbers, namely 640 and 40. These two numbers are compatible for division because:
64 ÷ 4 = 16
So, we have used mental arithmetic to solve a more complex problem.
Answer: 
Step-by-step explanation:
You should get this answer because the simpliest form of a radical is that you shouldn't have any radical in the denominator. In order to get rid of the radical sign in the denominator, you have to multiply the numerator and the denominator with the 
.
Look at the image below for further explanation
50 / 0.35 =Z
Z=160
Hope it helps!
The center is (0,0).
The radius is 7.
You're looking for the percent, so your equation would be:
x% × 200 = 0.5
(x/100) × 200 = 0.5
2x = 0.5
x = 0.25
So, 0.25% of 200 is 0.5.
* You can check your work by multiplying 0.25% × 200. Surely enough, it does give you 0.5.
Answer = 0.25%
