根据javascriptcanvas中的角度绘制等腰三角形

Draw isocele triangle according to angle in javascript canvas

我想知道如何在canvas中画一个等腰三角形,如果我知道第一个角,以及两个等边的长度。

Shema (known lengths are in red)

第二个问题,是否可以像这样弯曲顶部:

Shema

var canvas = document.getElementById("canvas");
canvas.width = 500;
canvas.height = 500;
 
var ctx = canvas.getContext("2d");
   ctx.closePath();
    ctx.save();

function drawPie(ctx,centerX, centerY, radius, startAngle, endAngle ){
    
        ctx.beginPath();
        ctx.moveTo(centerX,centerY);
        ctx.arc(centerX, centerY, radius, startAngle, endAngle);
        ctx.closePath();
        ctx.stroke();
    }

drawPie(ctx, 200,200,200,  -0.65*Math.PI, -0.60* Math.PI + Math.PI/4);
 <canvas id="canvas"></canvas>