- Volume Calculator
- Area Calculator
- Perimeter Calculator
- Surface Area Calculator
- Circle Calculator
- Rectangle Calculator
- Triangle Calculator
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Triangle Classification by Sides CalculatorClassify a triangle as equilateral, isosceles, or scalene from its three side lengths. Free instant calculator with a built-in valid-triangle check.
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Angle Between Two Lines CalculatorFind the acute angle between two straight lines from their slopes m₁ and m₂ using θ = arctan(|(m₁−m₂)/(1+m₁m₂)|). Get the result in degrees and radians.
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Scalene Triangle Perimeter CalculatorCalculate the perimeter of a scalene triangle by adding its three unequal sides: P = a + b + c. Fast, accurate, free online tool.
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Triangle Median CalculatorCalculate the three medians of a triangle from its side lengths using the median length formula. Free, instant, and accurate triangle median solver.
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Incircle of a Triangle CalculatorFind the inradius and incircle of a triangle from its three sides. Computes inradius r = Area/s with Heron's formula, plus incircle area and circumference.
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Triangle Side from Two Sides & Included Angle (Law of Cosines)Find the third side of a triangle from two sides and the included angle using the Law of Cosines: c = √(a² + b² − 2ab·cosC). Free, instant.
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Right Triangle Legs from Hypotenuse and Angle CalculatorFind both legs of a right triangle from the hypotenuse and an acute angle. Computes opposite = c·sinθ and adjacent = c·cosθ instantly.
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Right Triangle CalculatorSolve a right triangle from two sides: find the missing side, perimeter, area, all three altitudes and interior angles using the Pythagorean theorem.
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Law of Sines CalculatorSolve a triangle with the Law of Sines: find a missing angle or side, then get all sides, all angles, perimeter, area, inradius and circumradius.
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Isosceles Triangle CalculatorEnter the equal leg a and base b of an isosceles triangle to compute the third side, perimeter, semiperimeter, area and all three altitudes instantly.
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Triangle Theorems Calculator (AAA, AAS, ASA, ASS/SSA, SAS, SSS)Solve any triangle from AAA, AAS, ASA, ASS/SSA, SAS or SSS inputs. Get all angles, sides, perimeter, area, inradius and circumradius instantly.
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Law of Cosines CalculatorSolve any triangle with the Law of Cosines. Enter three sides (SSS) to find all angles, perimeter, area, inradius and circumradius instantly.
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Pythagorean Theorem CalculatorSolve the Pythagorean theorem a² + b² = c² for any missing side of a right triangle (leg a, leg b, or hypotenuse c) and get the area instantly.
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Area of Triangle with Coordinates CalculatorFind the area of a triangle from the coordinates of its three vertices using the shoelace formula. Enter (x,y) points and get the exact area instantly.
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Triangle Area CalculatorCalculate triangle area easily with base and height inputs. Get accurate results for your geometry problems and mathematical calculations with this simple and efficient triangle area calculator.
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Triangle CalculatorTriangle Calculator
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Trig Triangle CalculatorSolve a triangle from two sides and the included angle (SAS) using the law of cosines and law of sines. Finds the third side, angles, area, and perimeter.
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Solve Similar Triangles CalculatorSolve similar triangles instantly. Enter the sides of triangle 1 and one matching side of triangle 2 to find the scale factor k and the remaining sides.
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Law of Sines Triangle CalculatorSolve a triangle with the Law of Sines. Enter side a, angle A and angle B to find angle C, sides b and c, plus perimeter and area.
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Similar Right Triangles CalculatorCalculate the altitude and legs of a right triangle using the geometric mean relationships from the two hypotenuse segments p and q.
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Scalene Triangle Area CalculatorFind the area of a scalene triangle from its three sides using Heron's formula. Enter sides a, b and c to get area, perimeter and semi-perimeter instantly.
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SAS Triangle CalculatorSolve a triangle from two sides and the included angle (SAS). Find the third side with the Law of Cosines, plus area and remaining angles.
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Right Triangle Trigonometry CalculatorSolve a right triangle from its two legs: get the hypotenuse, sin, cos, tan, both acute angles, area and perimeter instantly with steps.
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Triangle Side and Angle CalculatorSolve a triangle from two sides and the included angle (SAS). Find the third side, remaining angles, perimeter and area using the Law of Cosines and Sines.
