Triangle Inequality Checker Can three sides form a triangle? Side a Side b Side c Forms a triangle? No Step-by-step with your numbers: 1. Values used: 2. Side a = 3 3. Side b = 4 4. Side c = 8 5. Forms a triangle? = No Did we solve your problem today? 👍 Yes 👎 No Thanks for the feedback! Sum of any two sides > third side. FAQ 3-4-8? No — 3+4=7 which is ≤ 8. Related calculators Heron's Formula Calculator Find a triangle's area from its three sides. Right Triangle Calculator Solve a right triangle from its two legs. Triangle Angle Calculator Find the third angle of a triangle.