Math Problem Statement

Given A(−1,2) and B(3,6) , find the coordinates of point X on AB¯¯¯¯¯¯¯¯ such that the ratio of AX to XB is 3:5.

Solution

To find the coordinates of point XX on line segment AB\overline{AB} such that the ratio of AXAX to XBXB is 3:5, we can use the section formula.

The section formula states that if a point divides a line segment in a given ratio, the coordinates of that point can be found using:

X=(mx2+nx1m+n,my2+ny1m+n)X = \left( \frac{m x_2 + n x_1}{m+n}, \frac{m y_2 + n y_1}{m+n} \right)

Where:

  • (x1,y1)(x_1, y_1) and (x2,y2)(x_2, y_2) are the coordinates of points AA and BB,
  • m:nm:n is the given ratio of AXAX to XBXB.

In this case:

  • A(1,2)A(-1, 2), B(3,6)B(3, 6),
  • m:n=3:5m:n = 3:5.

Now, applying the section formula:

X=(5(3)+3(1)3+5,5(6)+3(2)3+5)X = \left( \frac{5(3) + 3(-1)}{3+5}, \frac{5(6) + 3(2)}{3+5} \right)

First, calculate the xx-coordinate:

x=5(3)+3(1)8=1538=128=1.5x = \frac{5(3) + 3(-1)}{8} = \frac{15 - 3}{8} = \frac{12}{8} = 1.5

Next, calculate the yy-coordinate:

y=5(6)+3(2)8=30+68=368=4.5y = \frac{5(6) + 3(2)}{8} = \frac{30 + 6}{8} = \frac{36}{8} = 4.5

Thus, the coordinates of point XX are (1.5,4.5)(1.5, 4.5).

Summary:

The coordinates of point XX are (1.5,4.5)\boxed{(1.5, 4.5)}.

Would you like any further details or explanations?


Here are some related questions for practice:

  1. Find the coordinates of point XX dividing the line segment in the ratio 2:3.
  2. How would the section formula change if AXAX to XBXB was 5:3?
  3. What are the coordinates of the midpoint of AB\overline{AB}?
  4. How do you apply the section formula when the ratio involves negative numbers?
  5. Can you derive the section formula from basic geometry?

Tip: Always label your points clearly in geometry problems, as it helps to avoid confusion when applying formulas.

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Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Ratio and Proportion
Section Formula

Formulas

Section formula: (X, Y) = ( (m*x2 + n*x1)/(m+n), (m*y2 + n*y1)/(m+n) )

Theorems

Section formula theorem

Suitable Grade Level

Grades 9-10