What is wrong with this reasoning when calculating circle perimeter?
2786
The staircase paradox, or why $\pi\ne4$
115677
Prove the equality of circle's areas
99956
How to calculate the radius of the image circle?
125171
Help with this trigonometry problem?
48477
Finding an equation of circle which passes through three points
110352
Why is a full turn of the circle 360°? Why not any other number?
123532
An incorrect answer for an integral
143967
Finding an equation for a circle given its center and a point through which it passes
134722
Intersection of straight line and circle
79983
Finding the exact area of a circle?
30625
Does the square or the circle have the greater perimeter? A surprisingly hard problem for high schoolers
137391
How does the unit circle work for trigonometric ratios of non-acute angles?
135813
Soving a Complex Integral along a circle
24440
Revolving Beacon confusing calculus problem
138466
Calculating intersection of two Circles
31410
Why do the measurements of this object seem erroneous?
5435
Radius on beveled curve incorrect