Plot 1. error as function of θ and distance

r=.1; n=100; k=5; Clear[d];
pa=Plot3D[-180/Pi PolygonSimpErr[n,r,d,θ,k],{θ,0,Pi/2},{d,.5,8}];
pb=Plot3D[-180/Pi VptDepSimpErr[n,r,d,θ,k],{θ,0,Pi/2},{d,.5,8}
];
pc=Plot3D[-180/Pi SimpleImposterErr[n,r,d,θ,k],{θ,0,Pi/2},{d,.5,8}
];
pd=Plot3D[-180/Pi MeshedImposterErr[n,r,d,θ,k],{θ,0,Pi/2},{d,.5,8}
];
pe=Plot3D[-180/Pi IwDErr[n,r,d,θ,k],{θ,0,Pi/2},{d,.5,8}
];