var board = JXG.JSXGraph.initBoard('box1', {
boundingbox: [-10, 10, 10, -10],showNavigation:false, showcopyright: false, axis: false,
});
var p1 = board.create('point', [-8, 4],{face:'',fixed:true});
var p2 = board.create('point', [-8, -4],{face:'',fixed:true});
var p3 = board.create('point', [0, -4],{face:'',fixed:true});
var l1 = board.create('segment', [p1, p2],);
var l2 = board.create('segment', [p2, p3]);
var l3 = board.create('segment', [p3, p1]);
//var tm1 = board.create('tapemeasure', [[1, 2], [4, 2]], {name:'dist'});
var a1 = board.create('angle', [p1, p3, p2],{name:'45°', radius:1.5,label:{offset:[-8,-2]}});
var p4 = board.create('point', [0, 4],{name:'',face:'',fixed:true});
var l4 = board.create('segment', [p3, p4],{dash:2});
var l5 = board.create('segment', [p1, p4],{dash:2});
