• SSS Triangle Calculator
    Solve any triangle from its three sides (SSS) using the Law of Cosines. Get all three angles, perimeter, and area instantly with worked steps.
  • Tangent Ratio Calculator
    Calculate the tangent ratio of an angle in a right triangle from the opposite and adjacent sides, plus the angle in degrees. Free trig tool.
  • Obtuse Triangle Calculator
    Solve a triangle from two sides and the included angle. Find the third side, area, perimeter, all angles, and whether the triangle is obtuse.
  • Isosceles Triangle Leg Length Calculator
    Find the equal leg length (a) of an isosceles triangle from its base and height. Also computes perimeter and area instantly.
  • Oblique Triangle Calculator
    Solve any oblique (non-right) triangle from 3 known parts using the law of sines and law of cosines. Find missing sides, angles, perimeter and area.
  • Square Feet of a Triangle Calculator
    Calculate the area of a triangle in square feet from its base and height. Instantly converts to square yards and square meters too.
  • Pythagoras Triangle Calculator
    Calculate the hypotenuse of a right triangle from its two legs using the Pythagorean theorem c = √(a² + b²). Also shows area and perimeter.
  • Perimeter of a Triangle with Fractions Calculator
    Find the perimeter of a triangle whose sides are fractions. Enter each side as numerator/denominator and get P = a + b + c instantly.
  • Perimeter of a Triangle with Vertices Calculator
    Find the perimeter of a triangle from its three vertex coordinates (x, y). Uses the distance formula to sum all three side lengths instantly.
  • Perimeter of a Right Triangle Calculator
    Calculate the perimeter of a right triangle from its two legs. Enter leg a and leg b to get the hypotenuse and total perimeter instantly.
  • Triangle Interior and Exterior Angles Calculator
    Find the third interior angle and all three exterior angles of any triangle from two known interior angles. Uses the 180° angle-sum rule.
  • Missing Side of a Right Triangle Calculator
    Find the missing side of a right triangle using the Pythagorean theorem. Solve for the hypotenuse or a leg from any two known sides instantly.
  • Midsegment of a Triangle Calculator
    Find the midsegment of a triangle instantly. Enter the base side and get the parallel midsegment length, which equals half the base.
  • Isosceles Triangle Side Calculator
    Find the leg or base of an isosceles triangle from a known side and base angle. Uses leg = base/(2·cos θ) and base = 2·leg·cos θ.
  • Isosceles Triangle Angles Calculator
    Find the missing angles of an isosceles triangle. Enter a base angle or the vertex angle and instantly get the remaining angles.
  • Is it a Right Triangle Calculator
    Check if three side lengths form a right triangle. Enter sides a, b and c — we test the Pythagorean theorem a² + b² = c² instantly.
  • Isosceles Right Triangle Hypotenuse Calculator
    Find the hypotenuse of an isosceles right triangle from one leg using hypotenuse = leg × √2. Also returns area and perimeter instantly.
  • Isosceles Right Triangle Calculator
    Calculate the hypotenuse, area, and perimeter of an isosceles right triangle from its leg length using a=a, hyp=a√2, area=a²/2.
  • Cosine Rule Triangle Calculator
    Solve a triangle with the law of cosines. Enter two sides and the included angle to find the third side, remaining angles, perimeter, and area.
  • Triangle Inequality Theorem Calculator
    Check if three side lengths can form a valid triangle using the triangle inequality theorem: a+b>c, a+c>b, and b+c>a.
  • Triangle Area Calculator (SAS)
    Calculate the area of a triangle from two sides and their included angle (SAS) using Area = ½·a·b·sin(C). Fast, accurate, free.
  • Circumcenter Calculator
    Find the circumcenter of a triangle from three vertex coordinates. Computes Ux, Uy and the circumradius using perpendicular-bisector equations.
  • Centroid of a Triangle Calculator
    Find the centroid (G) of a triangle from its three vertex coordinates. Enter (x,y) for each corner to get the exact center of mass instantly.
  • Area of Triangle with Coordinates Calculator
    Find 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.