๐Ÿ“ Math

Triangle Calculator

Solve any triangle given 3 known values (angles or sides, with at least one side). Uses the Law of Sines and Law of Cosines to calculate the missing properties.

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Formula

Law of Sines: a/sin(A) = b/sin(B) = c/sin(C) | Law of Cosines: cยฒ = aยฒ + bยฒ - 2abยทcos(C)
a, b, c
Side lengths
A, B, C
Opposite angles

Example

Solving a Right Triangle

Find the hypotenuse and remaining angles given two legs a=3, b=4, and angle C=90ยฐ.

  1. Use Pythagorean theorem for side c: cยฒ = 3ยฒ + 4ยฒ = 9 + 16 = 25.
  2. Side c = โˆš25 = 5.
  3. Find angle A using sin(A) = a/c: sin(A) = 3/5 = 0.6.
  4. Angle A = arcsin(0.6) โ‰ˆ 36.87ยฐ.
  5. Find angle B: 180ยฐ - 90ยฐ - 36.87ยฐ = 53.13ยฐ.

Frequently Asked Questions

No. While knowing three angles defines the shape of the triangle, it does not define its size (these are known as similar triangles). You need at least one side length to calculate the exact dimensions.
When you are given two sides and an angle not between them (Side-Side-Angle), there can sometimes be two valid triangles, one valid triangle, or no possible triangle that fits the criteria.

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