Triangle Explorer
Triangle Explorer: Discover Types of Triangles
How does moving one corner change a triangle? Use this free interactive triangle tool to explore equilateral, isosceles, right, acute, and obtuse triangles. Drag the corners to change the shape, then compare its side lengths and angles. The triangle changes color and highlights matching types as you move.
What Makes Each Triangle Different?
- Equilateral: Three equal sides and three equal angles of 60°.
- Isosceles: At least two equal sides. Angles opposite equal sides are equal, too.
- Right: One angle measures exactly 90°.
- Acute: All three angles measure less than 90°.
- Obtuse: One angle measures more than 90°.
These names describe different properties, so a triangle can fit more than one type. An isosceles triangle can also be acute, right, or obtuse. Whatever its shape or size, a triangle has three sides, three vertices, and interior angles that add up to 180°.
How to Use Triangle Explorer
Select a triangle on the left to start with an example. Drag the dotted circles to move its corners freely. Select Angles or Side Lengths to show or hide measurements. Try making an isosceles right triangle, changing an acute triangle into an obtuse triangle, or creating three equal sides.
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