Drag the vertices to make the triangle roughly the shape you want.

At least one vertex must be moved before entering the triangle's data.

Click on three labels and enter the size of the angle or side.

Label the vertices , and

When you have entered three attributes click the button below:

In order to find all the attributes of a triangle at least three measurements are needed. In fact only three measurements are needed unless they are the three angles. In that case it is impossible to determine the lengths of the sides and the area as there are an infinite number of similar triangles with thise same three angles.

The following three relationships are used to find the unknown sides and angles.

The lengths of sides and size of angles must be all be positive numbers. Each angle must be less than 180^{o} and the longest side must be less than the sum of the shorter two sides.

Do you have any comments? It is always useful to receive feedback and helps make this free resource even more useful for those learning Mathematics anywhere in the world. Click here to enter your comments.

The code for this application was written by Transum using the wonderful functions written by Copyright (c) 2015 Project Nayuki and JS Fiddle.