Question

describe and correct the error a student made in finding the midpoint of cd with c(-4,5) and d(-1,-4).
choose the correct answer below.
a. the student used incorrect coordinates when calculating the midpoint.
b. the student swapped the x - and y - values when calculating the midpoint.
c. the student did not divide the numerator and denominator by 2 when calculating the midpoint.

Explanation:

Step1: Recall mid - point formula

The mid - point formula for two points $(x_1,y_1)$ and $(x_2,y_2)$ is $(\frac{x_1 + x_2}{2},\frac{y_1 + y_2}{2})$. For points $C(-4,5)$ and $D(-1,-4)$, the correct calculation for the x - coordinate of the mid - point is $\frac{-4+( - 1)}{2}=\frac{-4 - 1}{2}=-\frac{5}{2}$, and for the y - coordinate is $\frac{5+( - 4)}{2}=\frac{5 - 4}{2}=\frac{1}{2}$. The student's work $\frac{-4-( - 1)}{2}$ for the x - coordinate and $\frac{5-( - 4)}{2}$ for the y - coordinate is incorrect. The student used incorrect operations with the coordinates.

Answer:

A. The student used incorrect coordinates when calculating the midpoint.