Verify that the length from any point in a right triangle to the endpoints

						var board = JXG.JSXGraph.initBoard('box1', {
boundingbox: [-10, 10, 10, -10],showNavigation:false, showcopyright: false, axis: false,
});

var p1 = board.create('point', [-3.5, -4.0],{face:'',fixed:true,label:{offset:[-15,10]}});
var p2 = board.create('point', [4.5, -4.0],{face:'',fixed:true});
var p3 = board.create('point', [4.5, 7.0],{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 p4 = board.create('point', [2.5, 0],);
 var l1 = board.create('segment', [p4,p1],);
 var l2 = board.create('segment', [p4,p3],);