This question can be answered easiest using CALCULUS.
Basically, draw a an equation of a circle with radius r centered anywhere (say (0,0) for simplicity).
Then, find the inegral of y = sqrt(1 - x²) from 0 to r. There is a trig integral invovled and out pops ½πr² (because you only integrate starting with zero. Multiply by 2 to get the full area of the circle) . The integral represents the area under the curve so you get your answer.
If you haven't reach the level of calculus yet, there are geometric proofs, but they are pretty difficult to understand.
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Verified answer
Area = Pi(r)^2
3.14*radius*radius
This question can be answered easiest using CALCULUS.
Basically, draw a an equation of a circle with radius r centered anywhere (say (0,0) for simplicity).
Then, find the inegral of y = sqrt(1 - x²) from 0 to r. There is a trig integral invovled and out pops ½πr² (because you only integrate starting with zero. Multiply by 2 to get the full area of the circle) . The integral represents the area under the curve so you get your answer.
If you haven't reach the level of calculus yet, there are geometric proofs, but they are pretty difficult to understand.
πr²=the radius times the radius times Pi (of a circle of course)
Pi is 3.141592...... and going on forever with no distinct pattern. You can represent it by 22/7 if you like.
this is the formula for the area of a circle
A=area
r=radius