float Length_A = 3.5;
float Angle_B  = 52;
float Length_B = tan(radians(Angle_B)) * Length_A;

//get tangent length with known radius and angle
float ang = 180 - chf('angle');     
float rad = chf('radius');

float half_ang = (float)ang*0.5; // split the angle in half

float angA = (float)half_ang;// this is the angle atached to the curve halfed to aim at the center of the radius
float angC = (float)90.0; // tangent is always 90deg
float angB = (float)180.0 - (float)angC - (float)angA;// missing angle is center of radius

// lengths below are opposite to the angles above of the same ABC charaacter
// lenA/sin(angA) = lenB/sin(angB) = lenC/sin(angC) so need to cross multiply

float lenA = rad; // this is the opposite edge
float lenB = lenA * tan(radians(angB)); // needed edge length
//float lenC = lenA * sin(angC); // long edge

float tan_len = 0;

if (angA >= 45){
    tan_len = -lenB;
}
else {
    tan_len = lenB;
}

f@pscale =  tan_len;