Integer triangle not) satisfy formula_151. We can generate the full equivalence class of similar triangles that satisfy B=3A by using the formulas where formula_28 and formula_27 are integers such that formula_157. Note that all triangles with B = 3A (whether with integer sides or not) satisfy formula_158. The only integer triangle with three rational angles (rational numbers of degrees, or equivalently rational fractions of a full turn) is the equilateral triangle. This is because integer sides imply three rational cosines by the law of cosines, and by Niven's theorem a rational cosine coincides with a rational angle if and only if the
Triangle length of the other sides and the angle opposite to the unknown side. As per the law: For a triangle with length of sides "a", "b", "c" and angles of α, β, γ respectively, given two known lengths of a triangle "a" and "b", and the angle between the two known sides γ (or the angle opposite to the unknown side "c"), to calculate the third side "c", the following formula can be used: If the lengths of all three sides of any triangle are known the three angles can be calculated: The law of tangents, or tangent rule, can