Which triangle is a 30°-60°-90° triangle?

In a 30°-60°-90 ° triangle the sides are in the ratio 1 : 2 :. (For the definition of measuring angles by "degrees," see Topic 12.) Note that the smallest side, 1, is opposite the smallest angle, 30 °; while the largest side, 2, is opposite the largest angle, 90 °. (Theorem 6).