Geometry and Matrix Calculators
These calculators handle shapes and coordinates. The Triangle Calculator solves a triangle from any three known values, including the ambiguous two-sides-and-an-angle case, and covers right triangles and the Pythagorean theorem. The Area and Volume Calculators cover the shapes and solids that come up in school and in practical jobs, and the Slope Calculator turns two points into a gradient, an angle, a distance and a line equation.
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All Geometry Calculators (5)
Triangle Calculator
Solve any triangle from three values, including right trianglesArea Calculator
Area of rectangles, circles, triangles, trapezoids and other shapesVolume Calculator
Volume and surface area of cubes, cylinders, spheres, cones and moreSlope Calculator
Slope, angle, distance and line equation from two pointsMatrix Calculator
Add, multiply, invert and find determinants of matrices
Which tool do I need?
Find the missing side of a right triangle
Enter the two known sides to get the third with the Pythagorean theorem, plus the angles and area.
Work out how much a round tank or a cylinder holds
Pick the cylinder, enter the radius and height, and read the volume in cubic units and litres or gallons.
Get the equation of a line through two points
Enter both points to see the slope, the angle, the distance between them and the line in slope-intercept form.
About Geometry Calculators
The Matrix Calculator sits here because matrices are the language of transformations in geometry and graphics. It adds, multiplies and transposes matrices and finds determinants and inverses, flagging when a matrix has no inverse.
Units are kept consistent: enter lengths in one unit and areas and volumes come back in the matching square or cubic unit. Angles can be entered in degrees or radians. For flooring, concrete and other material estimates, the Construction & Home calculators apply the same geometry with waste allowances built in.
Guides
- Solving Triangles and Slopes: Sines, Cosines and Rise Over RunWhich law to use for SSS, SAS, ASA and SSA, why the ambiguous case has two answers, and how slope, angle and percent grade relate on a ramp or a roof.
- Area and Volume Formulas, and Why They WorkWhere the formulas for triangles, circles, cones and spheres come from, how square and cubic units convert, and the measuring mistakes that matter more than the maths.
- Matrix Operations by Hand: Determinant, Inverse and Row ReductionHow row operations drive the determinant, inverse, rank and RREF, why order matters in matrix multiplication, and why exact fractions beat floating point on small matrices.
Frequently asked questions
Why can two sides and an angle give two different triangles?
When the known angle is not between the two known sides, the third side can sometimes swing to two valid positions. The Triangle Calculator detects this ambiguous case and shows both solutions.
What units do area and volume results use?
The square or cubic version of the length unit you entered. Enter metres and you get square or cubic metres; the volume tool also converts to litres and gallons.
When does a matrix have no inverse?
When its determinant is zero. That means its rows are linearly dependent, and the Matrix Calculator says so instead of returning an inverse.
Is slope the same as the angle of a line?
They are related but not equal. Slope is rise over run; the angle is the arctangent of the slope, so a slope of 1 is a 45 degree line.