A trangle geometric shape

							var board = JXG.JSXGraph.initBoard('box1', {
        axis: true, boundingbox: [-10, 10, 10, -10], showcopyright: false,keepaspectratio: true, zoom: true, axis: false,showNavigation: false,
    });
var p1 = board.create('point', [-8, -5],{name:'B', size: 1,face:"", color:'blue',fixed:true, label: {offset:[-15,10], color:'blue'}} );	
var p2 = board.create('point', [2, -5],{name:'A', size: 1,face:"", color:'blue', fixed:true,label: {offset:[15,10], color:'blue'}} );	
var po1 =  board.create('regularpolygon',[p1,p2,3], {visible:false, vertices:{face:'',withLabel: false}});

var p3 = board.create('point', [po1.vertices[2].X(), po1.vertices[2].Y()],{name:'C',face:'', size: 1, fixed:true, color:'blue', label: {offset:[15,10], color:'blue'}} );

var po2 =  board.create('regularpolygon',[ po1.vertices[2],p2, 3], {visible:false, vertices:{face:'',withLabel: false}});

var p4 = board.create('point', [po2.vertices[2].X(), po2.vertices[2].Y()],{name:'D',face:'', fixed:true, size: 1, color:'blue', label: {offset:[15,10], color:'blue'}} );

var l1 = board.create('segment',[p1,p4],{strokeWidth:1,dash:2});

var l2 = board.create('segment',[p2,p3],{strokeWidth:1,dash:2});

var l3 = board.create('segment',[p1,p3],{strokeWidth:1});
var l4 = board.create('segment',[p1,p2],{strokeWidth:1});
var l5 = board.create('segment',[p2,p4],{strokeWidth:1});
var l6 = board.create('segment',[p3,p4],{strokeWidth:1});
var i1 =  board.create('intersection',[l1, l2],{name:"O",face:'',label: {offset:[0,15]}})