Hi so it's ask for area of circle an you know that formula for area of circle is πr2 r (radius)
What is π? We have two formula π which is 22/7 or 3.142.So for this question i will use 22/7.
If you look at question 2,4 and 6 you can see the diameter which line straight to the circumference. That's call diameter. But in the formula it want r which mean radius. So the diameter÷2