Triangles drawn to scale, labeled for students
The Triangle Generator draws a triangle to scale from any three of its measures: three sides, two sides and an angle, or two angles and a side. It works out the rest, so the picture always matches the numbers. Measures can be typed with fractions, square roots and π, like 5/2 or 3√2.
Label each side and angle with its measure, with math like x or 2y + 1, or with nothing, and add congruence marks, heights and right-angle squares. Teachers use it for the Pythagorean theorem, special right triangles, trigonometry, the laws of sines and cosines, and area.
What you can set
- Any three sides and angles, typed as numbers, fractions, square roots or π
- A label on each side and angle: its measure, text like x, or nothing
- Congruence ticks on sides and congruence arcs on angles, one to three of each
- A height from any corner, solid, dashed or dotted, labeled and with the point where it lands named
- Corner names, a unit such as cm or ft, and solved measures rounded to whole numbers, tenths or hundredths
- Right-angle squares on or off, which side sits at the bottom, flip and turn, and labels dragged where you want them
Copying, printing and sharing
Copy the figure straight into a test, worksheet or slide, or download it as a PNG or SVG. Printing the page prints
just the figure. Share link copies the page’s address with your settings in it, so anyone who opens it sees this
exact figure, and presets save settings you use often in your browser. It’s free, with no sign-up.
Frequently asked questions
Which measures do I need to give?
Any three that make a triangle: three sides (SSS), two sides and an angle (SAS or SSA), or two angles and a side (ASA or AAS). Three angles alone fix the shape but not the size, so no side lengths are shown. If the measures don’t make a triangle, the settings say why and the last good triangle stays on screen.
How do I label a side x for students to find?
Leave that side’s measure blank so the generator solves it, then set its label to text and type x, or any math like 2y + 1. A side or angle you gave shows its measure; one the generator solved shows nothing unless you ask for its measure.
Is the triangle really drawn to scale?
Yes. Its sides and angles are in proportion to the measures, so a 3-4-5 triangle looks like one. It isn’t true size on paper; it is fitted to the figure.
What about the ambiguous case?
When two sides and an angle not between them make two different triangles, the generator draws the one whose unknown angle is acute and offers Show the other triangle to switch to the second.
Can I type a square root or a fraction?
Yes. Type sqrt for √, / for a fraction and pi for π, so 5√2 or 7/2 are drawn at their true length and labeled as typed.
Math Figures Triangle Generator