Triangle Equations

[formlesstree4]

These are some equations you can use to calculate Sides and Angles of triangles. Correctly used, one may solve the entire triangle with just a few sides and angles.

#Region " Sines "
 
        Private Function FindSineAngle(ByVal Side1 As Double, ByVal Side2 As Double, ByVal Angle As Double) As Double
            Return RadianToDegree(Math.Asin((Side1 / Side2) * (Math.Sin(DegreeToRadian(Angle)))))
        End Function
 
        Private Function FindSineSide(ByVal Side As Double, ByVal Angle1 As Double, ByVal Angle2 As Double) As Double
            Return Side * ((Math.Sin(DegreeToRadian(Angle1)) / Math.Sin(DegreeToRadian(Angle2))))
        End Function
#End Region
 
#Region " Cosines "
        Friend Function FindCosineSide(ByVal Side1 As Double, ByVal Side2 As Double, ByVal Angle As Double) As Double
            'Get our variables setup and preprocessed for ease
            Dim Side1A As Double = Side1 ^ 2.0R
            Dim Side2A As Double = Side2 ^ 2.0R
 
            'Setup Formula
            Return Math.Sqrt((Side1A + Side2A) - (2.0R * Side1 * Side2 * System.Math.Cos(DegreeToRadian(Angle))))
        End Function
 
        Private Function FindCosineAngle(ByVal A As Double, ByVal B As Double, ByVal C As Double, ByVal Angle As CosineAngles) As Double
            Dim SideA As Double = A ^ 2.0R
            Dim SideB As Double = B ^ 2.0R
            Dim SideC As Double = C ^ 2.0R
            Dim Output As Double = Double.NaN
 
            Select Case Angle
                Case CosineAngles.AngleA
                    Output = RadianToDegree(Math.Acos((SideA - SideB - SideC) / (-2.0R * B * C)))
                Case CosineAngles.AngleB
                    Output = RadianToDegree(Math.Acos((SideB - SideA - SideC) / (-2.0R * A * C)))
                Case CosineAngles.AngleC
                    Output = RadianToDegree(Math.Acos((SideC - SideB - SideA) / (-2.0R * A * B)))
            End Select
 
            Return Output
        End Function
#End Region

Enjoy.