Re: [NTG-context] METAPOST -- specifying an unknown point coordinate by giving the angle from another known point

James, How about this. BL:=87; z0=origin; z1=(5,0); z4=dir(BL); % Intermediate point z3=10/y4*z4; z2=z3+z1; or alternatively without having to define z4 BL:=87; z0=origin; z1=(5,0); z3=10/(ypart dir(BL))*dir(BL); z2=z3+z1;