Question

Kendra is determining the distance between the points (6, 8) and (2, –3). Her work is shown below.

Step 1: d = StartRoot (6 minus 2) squared + (8 minus 3) squared EndRoot
Step 2: d = StartRoot (4) squared + (5) squared EndRoot
Step 3: d = StartRoot 16 + 25 EndRoot
Step 4: d = StartRoot 41 EndRoot

Which best describes the accuracy of Kendra’s solution?
Her solution is correct.
Her solution is incorrect. She subtracted before squaring.
Her solution is incorrect. She made an error when substituting the x-values into the equation.
Her solution is incorrect. She made an error when substituting the y-values into the equation.

Answer 1

Her solution is incorrect. She made an error when substituting the y-values.

Correct: d = sqrt((6−2)^2 + (8−(−3))^2) = sqrt(4^2 + 11^2) = sqrt(16 + 121) = sqrt(137).