Circular Geoboard for School Maths Lab

Quick Answer: Circular Geoboard for School Maths Lab is a board with pins arranged around a circle, on which students stretch rubber bands to make chords, inscribed polygons and angles. The circular geoboard turns circle geometry into something students build and measure for themselves.

What a Ring of Pins Lets Students Build

On a square geoboard, pins sit on a grid; on a circular one they sit on a circle, usually equally spaced and often with a pin at the centre. That layout suits anything inscribed in a circle. A band stretched between two pins is a chord, a band from the centre pin to the rim is a radius, one passing through the centre is a diameter, and joining several rim pins makes an inscribed polygon whose vertices all lie on the circle.

The board is a natural place to test circle theorems. Students fix two pins as the ends of an arc, stretch bands from both to the centre and to a third pin on the circle, and measure the two angles: the angle at the centre is twice the one at the circumference. Moving the third pin leaves that angle unchanged, and using a diameter gives a right angle. Four rim pins joined in order make a cyclic quadrilateral whose opposite angles can be measured and added.

Where the pins are equally spaced, the board also shows fractions of a turn. Knowing the pin count, students work out the angle between neighbouring pins at the centre and build regular polygons by skipping pins in a fixed pattern. The number of pins, the board size and whether rubber bands are supplied should be confirmed before ordering.

Applications

• Constructing chords, radii and diameters and comparing their lengths
• Verifying that the angle at the centre is double the angle at the circumference
• Building cyclic quadrilaterals and checking their opposite angles
• Making regular polygons by joining equally spaced pins
• Working out angles at the centre as fractions of 360 degrees

Specifications

Care & Handling

• Remove rubber bands after each lesson; bands left stretched lose elasticity and can loosen pins.
• Check that pins are firm and free of sharp burrs before handing boards to students.
• Store boards flat with nothing heavy resting on the pins.
• Remind students not to flick bands, which can snap back towards faces.

Why Choose LabEquip

Maths teachers who want every student to test circle theorems, rather than watch a demonstration, buy circular geoboards in class sets. LabEquip lists them in the Mathematics School Lab Products range with the Angle in a circle model for teacher demonstrations; send your quantities through the contact page.

Frequently Asked Questions

What is the difference between a circular and a square geoboard?

A square geoboard has pins on a grid and suits area, perimeter and coordinates. A circular board has pins on a circle, usually with a centre pin, and suits chords, inscribed polygons, angles at the centre and circle theorems.

How do students verify the angle at the centre theorem on the board?

Choose two pins as the ends of an arc, band them to the centre and to a third pin on the circle, and measure both angles with a protractor. The angle at the centre comes out twice the angle at the circumference.

How can regular polygons be made?

Join pins that are equally spaced around the circle. On a board with twelve equal rim pins, joining every third pin makes a square, every second pin a regular hexagon and every fourth pin an equilateral triangle.

How do you find the angle between neighbouring pins?

Divide 360 degrees by the number of equally spaced rim pins. With twelve pins, neighbouring pins are 30 degrees apart at the centre, which students can check with a protractor.

What kind of rubber bands work well?

Ordinary stationery bands of a size that stretches across the board without too much tension. Several colours help when two figures share pins, for example a chord and the angle it subtends.

Is the board suitable for younger students?

Yes, for simpler tasks such as making shapes, counting sides and exploring symmetry, with supervision because of the stretched bands. Theorem work suits secondary classes.

Last Updated: September 2026