Check out example codes for "circle css animation". It will help you in understanding the concepts better.

Code Example 1

class ProgressRing extends React.Component {
  constructor(props) {
    super(props);

    const { radius, stroke } = this.props;

    this.normalizedRadius = radius - stroke * 2;
    this.circumference = this.normalizedRadius * 2 * Math.PI;
  }
}

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