input constantes; input geometriepoint1; input papiers; beginfig(1); affixe.B(u*(1,1))so; affixe.A(u*(1,3))o; affixe.C(u*(4,1))se; affixe.D(4/5[z.A,z.C rotatedabout(z.A,90)])n; affixe.E(2/7[z.A,z.C])s; affixe.F(2/7[z.A,z.D])n; draw triangle(A,B,C); draw z.A--z.D--z.C; draw z.E--z.F; draw codeperp(A,B,C,5); draw codeperp(D,A,C,5); endfig; beginfig(2); papierun((0,0),(11,9),orange); draw (u*(0,4))--(u*(11,4)) withpen pencircle scaled1.25bp; draw (u*(4,0))--(u*(4,9)) withpen pencircle scaled1.25bp; affixe.O(u*(4,4))so; affixec.I(u*(5,4))s; affixec.J(u*(4,5))o; affixe.K(2[z.O,z.J]); affixe.L(5[z.O,z.I]); draw demidroite(K,L,1.4); draw demidroite(L,K,1.8); label.rt(btex $(d_1)$ etex,u*(0,8)); endfig; beginfig(3); affixe.A(u*(1,1))so; affixe.B(u*(5,1))se; affixe.C(u*(7,3))ne; affixe.D(z.C shifted(z.A-z.B))no; affixe.O(1/2[z.A,z.C])s; affixe.S((xpart(z.O),7u))n; draw z.S--z.A--z.B--z.C--cycle--z.B; draw z.A--z.D--z.C dashed evenly; draw z.S--z.D--z.B dashed evenly; draw z.A--z.C dashed evenly; draw z.S--z.O dashed evenly; endfig; end