Points A(0,0) and B(8,6) are graphed in the coordinate plane. What is the distance from A to B?

Use the distance formula, which is the Pythagorean theorem applied to the horizontal and vertical differences: $d = \sqrt{(8 - 0)^2 + (6 - 0)^2} = \sqrt{64 + 36} = \sqrt{100} = 10$. This is a 3-4-5 triangle scaled by 2, since the legs 6 and 8 are $2 \cdot 3$ and $2 \cdot 4$, so the hypotenuse is $2 \cdot 5 = 10$. A common wrong answer is 14, which comes from adding the differences $8 + 6$ instead of using the Pythagorean theorem. Another is 100, from forgetting to take the square root. A third is 2, from subtracting.