What is 30-60-90 right triangle?

A 30-60-90 right triangle is one in which the three angles of the triangle 30, 60 and 90 degrees. The length of the sides of such a triangle have the ratio 1:2:square root of 3. The 1 is opposite the 30 degree angle, the 2 is opposite the 60 degree angle and the square root of 3 is opposite the 90 degree angle.