Math Problem Statement

solve

The points A, B, and C have coordinates (2,6), (6,1), and (p,q) respectively. Given that B is the midpoint of AC, find the equation of the line that passes through C and is perpendicular to AB. Give your answer in the form ax + by = c.

Solution

Let's solve the problem step by step.

Given:

  • Coordinates of A(2,6)A(2, 6), B(6,1)B(6, 1), and C(p,q)C(p, q).
  • BB is the midpoint of ACAC.
  • We need to find the equation of the line passing through C(p,q)C(p, q) and perpendicular to line ABAB, in the form ax+by=cax + by = c.

Step 1: Find the coordinates of C(p,q)C(p, q)

Since B(6,1)B(6, 1) is the midpoint of ACAC, we can use the midpoint formula to express the coordinates of CC.

Midpoint formula: (x1+x22,y1+y22)\left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right) where A(2,6)A(2, 6) and C(p,q)C(p, q) are the points, and B(6,1)B(6, 1) is the midpoint.

For the x-coordinate: 2+p2=6    2+p=12    p=10\frac{2 + p}{2} = 6 \implies 2 + p = 12 \implies p = 10

For the y-coordinate: 6+q2=1    6+q=2    q=4\frac{6 + q}{2} = 1 \implies 6 + q = 2 \implies q = -4

Thus, C(10,4)C(10, -4).

Step 2: Find the slope of line ABAB

The slope of line ABAB is given by: mAB=y2y1x2x1=1662=54m_{AB} = \frac{y_2 - y_1}{x_2 - x_1} = \frac{1 - 6}{6 - 2} = \frac{-5}{4}

Step 3: Find the slope of the line perpendicular to ABAB

The slope of the line perpendicular to ABAB is the negative reciprocal of mABm_{AB}: mperpendicular=45m_{\text{perpendicular}} = \frac{4}{5}

Step 4: Find the equation of the line passing through C(10,4)C(10, -4) and perpendicular to ABAB

Using the point-slope form of the equation of a line: yy1=m(xx1)y - y_1 = m(x - x_1) where m=45m = \frac{4}{5}, and (x1,y1)=(10,4)(x_1, y_1) = (10, -4).

Substitute the values: y+4=45(x10)y + 4 = \frac{4}{5}(x - 10) Multiply both sides by 5 to eliminate the fraction: 5(y+4)=4(x10)5(y + 4) = 4(x - 10) Simplify: 5y+20=4x405y + 20 = 4x - 40 Rearranging the terms: 4x5y=604x - 5y = 60

Thus, the equation of the line is: 4x5y=604x - 5y = 60

Final Answer:

The equation of the line is 4x5y=604x - 5y = 60.


Would you like more details or have any other questions? Here are 5 related questions:

  1. How do you find the equation of a line given two points?
  2. What is the midpoint formula and how can it be applied in other problems?
  3. How do you determine if two lines are perpendicular?
  4. Can you explain how to convert a point-slope form to standard form?
  5. How do you solve a system of equations involving two lines?

Tip: Always check if the problem involves perpendicular or parallel lines, as this gives valuable information about their slopes!

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Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Midpoint
Slopes of Lines
Perpendicular Lines

Formulas

Midpoint formula: ((x1 + x2) / 2, (y1 + y2) / 2)
Slope formula: (y2 - y1) / (x2 - x1)
Equation of a line in point-slope form: y - y1 = m(x - x1)

Theorems

Perpendicular Line Theorem (slopes of perpendicular lines are negative reciprocals)

Suitable Grade Level

Grades 9-11