A right-angled triangle has shorter sides of 6 cm and 8 cm. How long is the hypotenuse?

1. The sides of a right-angled triangle obey the Theorem of Pythagoras. 2. The square of the hypotenuse equals the sum of the squares of the two other sides. 3. Square the first short side: 6 times 6 is 36. 4. Square the second short side: 8 times 8 is 64. 5. Add them: 36 plus 64 is 100. 6. The hypotenuse is the number whose square is 100, which is 10, so the hypotenuse is 10 cm. 7. Answering 14 cm just adds the two short sides, which ignores the theorem. 8. Answering 48 cm multiplies them, which is the area trap rather than a length. _Source: Siyavula Mathematics Grade 10 (Everything Maths, CC BY 4.0), Chapter 5: Trigonometry_