# Isosceles triangle calculator

Please enter two properties of the isosceles triangle

Use symbols: a,b c, h, T, p, A, B, C, r, R

This calculator calculates any isosceles triangle specified by two of its properties. An isosceles triangle is a triangle where two sides have the same length. To calculate the properties of an isosceles triangle when given certain information, you can use the Pythagorean theorem, the Law of Cosines, or the Law of Sines.

If you know the lengths of two congruent sides (a,a) and the length of the non-congruent side (c) of an isosceles triangle, you can use the Law of Cosines to find the measure of the angles.

The Law of Cosines states that:
c2 = a2 + a2 - 2aa * cos(C)

where c is the length of the non-congruent side, a is the length of the congruent sides, and C is the measure of the angle opposite side c. By solving this equation you can find the value of cos(C) and then use the inverse cosine function (arccos) to find the measure of angle C in radians or degree.

Additionally, you can use the Law of Sines to find the measure of the angles, the formula is:

sin(A) = a/c * sin(C)

once you find the sine of angle A, you can use the inverse sine function (arcsin) to find the measure of angle A in radians or degree.

You can also use the given sides and angles to find the area of the triangle using Heron's formula or using trigonometric functions like Sin or Cos. (T=12 p=16).

### An isosceles triangle in word problems in mathematics:

#### Look also at our friend's collection of math problems and questions:

See triangle basics on Wikipedia or more details on solving triangles.