Rotate a point about an origin by a specified angle. Read more on Wikipedia and StackExchange.
The red point represents the rotation of the blue point around the black point by 45 degrees. By dragging, you can adjust the position of the blue point and the black point, and the angle of rotation of the red point.
This block uses Geometric.js for all geometric functions, specifically lineAngle, lineLength, lineMidpoint, pointRotate and pointTranslate.