Use a free geometry calculator with worked steps for right triangles, circles and rectangular prisms, including units and checks.
Enter the known values to see the answer and the working.
Geometry connects diagrams, measurements and constraints. These functions adapt MATHGPTNOW’s right-triangle, circle and volume routines to a compact Singapore learning tool. The calculator assumes the named dimensions are in one consistent unit and that a diagram satisfies the stated shape. Mark the right angle, radius or perpendicular height before entering anything; a formula only applies when those geometric conditions are true.
Identify equal sides, parallel lines, right angles, centres and perpendicular heights. A sloping side is not automatically a height, and the longest side is the hypotenuse only in a right-angled triangle. Redraw a crowded figure and label known values. This short step prevents most formula-selection errors.
Lengths must use the same unit before they are combined. Area uses square units because two perpendicular lengths are multiplied; volume uses cubic units because three dimensions are multiplied. Converting 1 metre to 100 centimetres does not mean 1 square metre equals 100 square centimetres. Convert each length first, then apply the formula.
Expressions involving π or square roots can be kept exact until the context requires a decimal. Early rounding can accumulate error, especially when a result is used in a later area or volume calculation. Record the exact relationship, then round the final value to a precision justified by the measurements.
A right-triangle hypotenuse must exceed either perpendicular side but remain below their sum. A circle’s circumference should be a little more than three diameters. Doubling every dimension of a prism multiplies its volume by eight. These relationships detect results that have the wrong formula, unit or entered dimension.
Read the purpose before entering values. Each mode answers a different mathematical question and needs a different final check.
| Mode and full guide | Use it to | Check the result |
|---|---|---|
| Right triangleOpen calculator → | Find the hypotenuse, area and perimeter from two perpendicular sides. | Square the reported hypotenuse and compare it with the sum of the two smaller squares. |
| CircleOpen calculator → | Find area, circumference and diameter from a positive radius. | Check that circumference divided by diameter is approximately π. |
| Rectangular prismOpen calculator → | Find volume and total surface area from length, width and height. | Confirm the volume uses cubic units and the surface area uses square units. |
No. The equation a² + b² = c² applies to a right-angled triangle, where a and b meet at ninety degrees and c is opposite that angle. Other triangles require different relationships or must first be divided into right triangles.
An exact answer such as 49π square centimetres preserves the full relationship. A decimal such as 153.94 square centimetres is an approximation based on a chosen value of π and rounding. Follow the question’s requested form.
Surface area measures the material covering the outside and uses square units. Volume measures the space inside and uses cubic units. A container problem may need one, the other or both, so read the requested quantity carefully.
No. It calculates selected measurements from entered dimensions. Draw or inspect the figure separately, because an unscaled sketch can still carry essential information about right angles, equal lengths and which measurement is missing.
Next, test geometry alongside other topics; You can also review Mathematics resource criteria; You can also revisit arithmetic and unit work.