.geometry "version 0.51";
.l0; 
.text("Construct a triangle given the length L of
a side, the angle \alpha adjacent to that side, and
the length of the median m from that angle.
Adjust L, \alpha, and m to experiment with the
figure.", .l0);
v1 = .free(-0.889222, 0.862275);
v2 = .free(-0.0688623, 0.859281);
v3 = .free(-0.700599, 0.790419);
v4 = .free(-0.88024, 0.658683);
v5 = .free(-0.682635, 0.658683);
v6 = .free(-0.898204, 0.571856);
v7 = .free(-0.494012, 0.568862);
l1 = .l.vv(v1, v2, "L");
l2 = .l.vv(v3, v4);
l4 = .l.vv(v6, v7, "m");
ang1 = .a.vvv(v5, v4, v3, "\alpha");
l3 = .l.vv(v4, v5);
v8 = .free(-0.245509, -0.0239521, "A");
c1 = .c.ctrvv(v8, v1, v2, .in);
v9 = .vonc(c1, 0.574856, -0.0239521, "B");
l5 = .l.vv(v8, v9, [.white, .blink, .white], "L");
v10 = .v.avv(ang1, v9, v8, .in);
l6 = .l.vv(v8, v10, [2 .in, .blink, .white], .ray12);
v11 = .v.vvmid(v8, v9, [.white, 2 .in, .blink, .white], "O");
c2 = .c.ctrvv(v11, v6, v7, [4 .in, .blink, .white]);
v12 = .v.lc(l6, c2, 2, [.white, 4 .in, .blink, .white], "C");
l7 = .l.vv(v12, v11, [.white, 4 .in, .white], "m");
ang2 = .a.vvv(v11, v8, v12, [.white, .in, .blink, .white], "\alpha");
l8 = .l.vv(v12, v9, [.white, 4 .in, .white]);
l9 = .l.vv(v12, v8, [.white, .in]);
.text("Make a segment of length L called AB.", .l1);
.text("Copy the angle \alpha at vertex A.", .l2);
.text("Find the midpoint O of segment AB.", .l3);
.text("Draw a circle centered at O of radius m.", .l4);
.text("The other vertex C of the triangle must line
on the line making angle \alpha with AB and on the circle
of radius m centered at O, so we are done.", .l5);
.text("Press 'Next' to continue ...", .red, .tol4);
v13 = .vonc(c2, -0.0953084, 0.285547, .in);
l10 = .l.vv(v11, v13, [4 .in, .blink1, .in], "m");