A student wants to find point C on the directed line segment from [tex]\(A\)[/tex] to [tex]\(B\)[/tex] on a number line such that the segment is partitioned in a ratio of [tex]\(3: 4\)[/tex]. Point [tex]\(A\)[/tex] is at -6 and point [tex]\(B\)[/tex] is at 2. The student's work is shown.

1. [tex]\(c=\left(\frac{3}{4}\right)(2-(-6))+(-6)\)[/tex]

2. [tex]\(c=\left(\frac{3}{4}\right)(8)-6\)[/tex]

3. [tex]\(c=6-6\)[/tex]

4. [tex]\(c=0\)[/tex]

Analyze the student's work. Is the answer correct? Explain.

A. No, the student should have added [tex]\(3+4\)[/tex] to get the total number of sections and used the fraction [tex]\(\frac{3}{7}\)[/tex] instead of [tex]\(\frac{3}{4}\)[/tex].

B. No, the student should have subtracted 2 from -6 to find the distance.

C. No, the student should have added 2 at the end to add to the starting point.

D. Yes, the student's answer is correct.



Answer :

To solve this problem accurately, you need to partition the line segment from point [tex]\( A \)[/tex] to point [tex]\( B \)[/tex] in the ratio [tex]\( 3:4 \)[/tex]. Here’s an appropriate step-by-step solution:

1. Point [tex]\( A \)[/tex] is at -6 and point [tex]\( B \)[/tex] is at 2.
2. The ratio given is [tex]\( 3:4 \)[/tex]. In order to find point [tex]\( C \)[/tex] that divides the segment [tex]\( AB \)[/tex] in this ratio, we need to use the fraction [tex]\( \frac{3}{3+4} = \frac{3}{7} \)[/tex].

Using the formula for the section of a line segment in a given ratio:
[tex]\[ C = A + \left(\frac{3}{3+4}\right) \times (B - A) \][/tex]
Here’s the calculation step-by-step:

1. Calculate the total distance between [tex]\( A \)[/tex] and [tex]\( B \)[/tex]:
[tex]\[ B - A = 2 - (-6) = 2 + 6 = 8 \][/tex]

2. Multiply this distance by the ratio [tex]\( \frac{3}{7} \)[/tex]:
[tex]\[ \frac{3}{7} \times 8 = \frac{24}{7} \approx 3.4285714285714284 \][/tex]

3. Add this result to point [tex]\( A \)[/tex]:
[tex]\[ A + \frac{24}{7} = -6 + \frac{24}{7} = - \frac{42}{7} + \frac{24}{7} = - \frac{42 - 24}{7} = - \frac{18}{7} = -2.5714285714285716\][/tex]

Therefore, the correct position of point [tex]\( C \)[/tex] is approximately [tex]\(-2.5714285714285716\)[/tex].

The student's work contained the following mistakes:
- The student used the incorrect formula; he/she used [tex]\( \frac{3}{4} \)[/tex] instead of the correct fraction [tex]\( \frac{3}{7} \)[/tex] for the partitioning ratio.
- The student subtracted 6, which is an incorrect approach because the correct approach is to simply add the resulting value to [tex]\( A \)[/tex].

So, the student's answer is not correct, and the proper method involves dividing by the sum of the parts of the ratio and then adding this to point [tex]\( A \)[/tex].