Make a triangle and label it using Canvas in Node.js

Question

I am trying to make something that looks like this:

I've written this so far:

const { createCanvas } = require('canvas');
 
class Trigonometry {
    constructor({ sides, angles }) {
        this.sides = sides;
        this.angles = angles;
    }
 
    drawCanvas() {
        const { a, b, c } = this.sides;
        const [SA, SB, SC] = this.scaleNumbers(a, b, c);
        const { A: AA, B: AB, C: AC } = this.angles;
 
        const canvas = createCanvas(300, 300);
        const ctx = canvas.getContext('2d');
 
        const ax = 0, ay = 0;
        const bx = SC, by = 0;
        const cx = (SB * SA + SC * SC - SA * SA) / (2 * SC);
        const cy = Math.sqrt(SB * SA + SC + cx * cx);
 
        const ox = canvas.width / 2 - bx / 2;
        const oy = canvas.height / 2 + cy / 2;
 
        // Draw triangle
        ctx.beginPath();
        ctx.moveTo(ox + ax, oy - ay);
        ctx.lineTo(ox + bx, oy - by);
        ctx.lineTo(ox + cx, oy - cy);
        ctx.lineTo(ox + ax, oy - ay);
        ctx.lineWidth = 2; ctx.fillStyle = 'grey';
        ctx.stroke(); ctx.fill();
        ctx.closePath();
 
        // Draw angle labels
        ctx.font = 'bold 15px Arial';
        ctx.fillStyle = 'blue';
        this.drawLabel(ctx, `A=${AA}°`, ox + ax, oy - ay);
        this.drawLabel(ctx, `B=${AB}°`, ox + bx, oy - by);
        this.drawLabel(ctx, `C=${AC}°`, ox + cx, oy - cy);
 
        // Draw line labels
        ctx.fillStyle = 'green';
        this.drawLabel(ctx, `a=${a}`, bx + cx / 2, by - cy / 2);
        this.drawLabel(ctx, `b=${b}`, ox + cx / 2, oy - cy / 2);
        this.drawLabel(ctx, `c=${c}`, ox + bx / 2, oy - by / 2);
 
        return canvas.toDataURL()
    }
 
    drawLabel(ctx, txt, x, y) {
        const { width } = ctx.measureText(txt);
        ctx.fillText(txt, x - width / 2, y);
    }
 
    scaleNumbers(...numbers) {
        if (numbers.every(n => n > 200 && n < 250)) return numbers;
        if (numbers.some(n => n > 250))
            return numbers.map(n => n / (Math.max(...numbers) / 250))
        return numbers.map(n => n * (250 / Math.min(...numbers)));
    }
}
 
const trig = new Trigonometry({
    sides: { a: 800, b: 750, c: 700 },
    angles: { A: 66.868, B: 59.556, C: 53.576 },
});

const data = trig.toDataURL();

But it doesn't result in exactly what I want, the triangle is simply wrong and it breaks a lot and simply looks bad.

All the line lengths and angles get calculated before hand so I have access to all of those. Maybe there is another way to do this without using canvas?