Hypotenuse 3,4,?

**The reasoning** This is a classic **Pythagorean theorem** question. In any right-angled triangle, the relationship between the sides is: **hypotenuse² = leg₁² + leg₂²** Here, the two shorter sides (legs) are 3 and 4. So: hypotenuse² = 3² + 4² hypotenuse² = 9 + 16 hypotenuse² = 25 hypotenuse = √25 = **5** This 3-4-5 triangle is the most famous Pythagorean triple—memorize it! Others include 5-12-13 and 8-15-17. **Why the wrong options tempt you** - **6, 7, 8**: Students often just add (3+4=7) or pick numbers close to the legs. Wrong! The hypotenuse isn't found by simple addition—you must square, add, then take the square root. - **6**: Maybe you thought "3×2=6"? Random multiplication doesn't work here. **Quick takeaway** The hypotenuse is always the *longest* side in a right triangle, and you find it using **a² + b² = c²**—never by adding or guessing. Burn "3-4-5" into your memory!