Constructing an Equilateral Triangle With Compass
This animation demonstrates the classic ruler-and-compass method for constructing an equilateral triangle with 5 cm sides. It shows drawing base segment AB, setting the compass to the fixed 5 cm radius, swinging arcs from A and B to locate point C, and joining the vertices. The visual emphasizes why equal compass radii guarantee three equal sides, reinforcing the logic behind classical geometric constructions for students learning compass-and-straightedge techniques.
16:9 · Preview before teaching · automatic layout checks do not establish subject accuracy
The prompt that made it
Create a clean, accurate educational mathematics animation showing how to construct an equilateral triangle with each side exactly 5 cm, using a ruler, pencil, and compass. Scene 1: On a clean white mathematical drawing sheet, use a ruler and pencil to draw a straight line segment AB exactly 5 cm long. Clearly label the endpoints “A” and “B” and show the measurement “5 cm”. Scene 2: Clearly show a realistic geometry compass (drawing compass) in close-up. The compass must be clearly visible, with one sharp point and one pencil leg. Set the compass opening exactly to 5 cm using the ruler. Scene 3: Place the sharp point of the compass precisely on point A. Keep the compass opening fixed at 5 cm and draw a smooth arc above line AB. Scene 4: Move the compass without changing its 5 cm opening. Place the sharp point precisely on point B and draw another arc intersecting the first arc. Scene 5: Clearly mark the intersection point as “C”. Scene 6: Use the ruler and pencil to draw straight lines from A to C and from B to C. The final result must clearly show triangle ABC with AB = BC = CA = 5 cm, forming a perfect equilateral triangle. Style: professional school mathematics lesson, realistic compass movement, precise geometry, smooth hand-drawn animation, white background, thin black construction lines, clear labels, no unnecessary decorations, no extra text, accurate proportions, educational and easy for students to understand. Camera: top-down view of the drawing paper, with close-up shots when using the compass. The compass must remain clearly visible during both arc constructions. Duration: 10–15 seconds. Aspect ratio: 16:9. High-resolution educational animation.
Make the next one in this series
- Show how to construct a perfect square using only a ruler and compass
- Demonstrate bisecting an angle with a compass and straightedge
- Animate constructing a regular hexagon inscribed in a circle using a compass
