A triangle has sides of length 5 cm, 12 cm, and 13 cm. Is it a right triangle?

Sun, 19 Apr 2026 18:05:57 +0000

**A triangle has sides of length 5 cm, 12 cm, and 13 cm. Is it a right triangle?** Curious about why that 5-12-13 triangle keeps popping up in conversations online? The short answer: yes, it absolutely is a right triangle—and understanding why matters more than you might expect. With rising interest in geometry fundamentals and visual design trends, this triangle remains a cornerstone example for both learners and creators. The triangle with sides 5 cm, 12 cm, and 13 cm isn’t just a random shape—it’s one of the most famous—notable integer-sided right triangles in history. Because 5² + 12² equals 25 + 144 = 169, and 13² equals 169, this matches the Pythagorean theorem exactly. This mathematical certainty makes it a reliable reference point in geometry education and visual thinking today. Despite its simplicity, the 5-12-13 triangle continues to intrigue users exploring math, design, and spatial reasoning online. The bold proportions command attention in mobile-friendly content, especially as more people engage with educational material through Discover feeds. Its clean, symmetrical form translates well into visuals, making it a trusted symbol in apps, infographics, and mental math tutorials.