JavaScript: Draw a right-angled triangle

Last update on July 18 2025 12:58:59 (UTC/GMT +8 hours)

JavaScript Drawing: Exercise-4 with Solution

Right-Angled Triangle

Write a JavaScript program to draw the following right-angled triangle.

Sample output:

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>Draw a right-angled triangle</title>
</head>
<body onload="draw();">
<canvas id="canvas" width="150" height="150"></canvas>
</body>
</html>

JavaScript Code:

function draw() 
{
  var canvas = document.getElementById('canvas');
  if (canvas.getContext)
  {
    var context = canvas.getContext('2d');

    context.beginPath();
    context.moveTo(75,75);
    context.lineTo(10,75);
    context.lineTo(10,25);
    context.fill();
  }
}

Live Demo:

See the Pen javascript-drawing-exercise-4 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

Write a JavaScript program to draw a right-angled triangle filled with a linear gradient from one vertex to another.
Write a JavaScript program to draw a right-angled triangle with a bold border and a subtle drop shadow.
Write a JavaScript program to draw multiple right-angled triangles that form a repeating pattern or tessellation.
Write a JavaScript program to animate the drawing of a right-angled triangle by progressively increasing the length of its sides.

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