The shortest side of a triangle is opposite the smallest angle. Image caption, All three sides of an equilateral triangle are the same length. The word equilateral means equal lines. Each angle is ...

225 + 135 = 360 The sum of interior angles in a triangle is 180˚. In an equilateral triangle, all three angles are equal to 60˚. To find the missing angles in an equilateral triangle ...

The ancient Greek mathematician Euclid proved in his Elements of Geometry that there are only five Platonic solids – the regular tetrahedron (four sides that are equilateral triangles), the cube (six ...