Interactive, free online geometry tool from GeoGebra: create triangles, circles, angles, transformations and much more!

Use the freehand shape tool to draw a few circles that pass through A and B. You may move the circles carefully after drawing. Use the mid-point tool to mark centre of each circle.

The general form of the equation of a circle. If that doesn't help, watch this video. Create your own. Draw a circle with radius 3.16. Write the equation. Identify the center and radius of the circle you drew above.

An interactive for exploring the coordinates and angles of the unit circle, as well as finding the patterns among both.

Create one fraction on each circle. Using , click and drag the center of one circle onto the other circle. Use the blue points to drag the fractions so that one edge aligns.

Triangle Maker. Author: Melanie Palma. Topic: Constructions, Triangles. What triangles can you create using the red, green, and blue side lengths? Adjust the lengths of the sides by dragging the endpoints. Adjust the angles in the triangle by dragging the endpoints along the circles.

Interactive, free online graphing calculator from GeoGebra: graph functions, plot data, drag sliders, and much more!

Interactive Circle Theorems. Angle in a semi-circle; Cyclic quadrilaterals; Angle made from the radius with a tangent; Angles in the same segment; Alternate Segment Theorem; The angle at the centre; One point two equal tangents

Interactive tool for exploring the coordinates and angles of the unit circle.

You can use this tool to perform rotations of quadrilaterals around the origin in the coordinate plane. Be sure to try to perform the rotation manually at first, but then feel free to use this tool to check your work and visualize the rotation.