Math Problem Statement

The line L1 shown on the set of axes below has equation 3x + 4y = 24. L1 cuts the x-axis at A and cuts the y-axis at B. (a) Write down the coordinates of A and B. (b) M is the midpoint of the line segment [AB]. Write down the coordinates of M. (c) The line L2 passes through the point M and the point C(0, −2). Write down the equation of L2. (d) Find the length of (i) MC; (ii) AC.

Solution

Let's break down and solve the problem step by step.

We are given that the line L1L_1 has the equation:

3x+4y=243x + 4y = 24

This line cuts the xx-axis at point AA and the yy-axis at point BB.

Part (a): Coordinates of A and B

To find the coordinates of AA (on the xx-axis) and BB (on the yy-axis):

  • At AA, the line intersects the xx-axis, so y=0y = 0: 3x+4(0)=24    3x=24    x=83x + 4(0) = 24 \implies 3x = 24 \implies x = 8 Hence, the coordinates of AA are (8,0)(8, 0).

  • At BB, the line intersects the yy-axis, so x=0x = 0: 3(0)+4y=24    4y=24    y=63(0) + 4y = 24 \implies 4y = 24 \implies y = 6 Hence, the coordinates of BB are (0,6)(0, 6).

Part (b): Coordinates of M

MM is the midpoint of line segment [AB][AB]. The midpoint formula is given by:

M=(x1+x22,y1+y22)M = \left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right)

Substituting the coordinates of A(8,0)A (8, 0) and B(0,6)B (0, 6):

M=(8+02,0+62)=(4,3)M = \left( \frac{8 + 0}{2}, \frac{0 + 6}{2} \right) = (4, 3)

Thus, the coordinates of MM are (4,3)(4, 3).

Part (c): Equation of Line L2L_2

We are given that line L2L_2 passes through points M(4,3)M(4, 3) and C(0,2)C(0, -2). To find the equation of line L2L_2, we first find the slope using the slope formula:

slope of L2=y2y1x2x1=3(2)40=54\text{slope of } L_2 = \frac{y_2 - y_1}{x_2 - x_1} = \frac{3 - (-2)}{4 - 0} = \frac{5}{4}

Now that we have the slope, we use the point-slope form of a line equation:

yy1=m(xx1)y - y_1 = m(x - x_1)

Using point M(4,3)M(4, 3):

y3=54(x4)y - 3 = \frac{5}{4}(x - 4)

Simplifying:

y3=54x5    y=54x5+3    y=54x2y - 3 = \frac{5}{4}x - 5 \implies y = \frac{5}{4}x - 5 + 3 \implies y = \frac{5}{4}x - 2

Thus, the equation of line L2L_2 is:

y=54x2y = \frac{5}{4}x - 2

Part (d): Lengths of MC and AC

  1. Length of MCMC:

Using the distance formula between points M(4,3)M(4, 3) and C(0,2)C(0, -2):

MC=(x2x1)2+(y2y1)2=(40)2+(3(2))2=42+(3+2)2=16+25=41MC = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} = \sqrt{(4 - 0)^2 + (3 - (-2))^2} = \sqrt{4^2 + (3 + 2)^2} = \sqrt{16 + 25} = \sqrt{41}

Thus, MC=41MC = \sqrt{41}.

  1. Length of ACAC:

Using the distance formula between points A(8,0)A(8, 0) and C(0,2)C(0, -2):

AC=(x2x1)2+(y2y1)2=(80)2+(0(2))2=82+22=64+4=68AC = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} = \sqrt{(8 - 0)^2 + (0 - (-2))^2} = \sqrt{8^2 + 2^2} = \sqrt{64 + 4} = \sqrt{68}

Thus, AC=68AC = \sqrt{68}.


Do you need further clarification on any part of the solution? Here are some related questions you can explore:

  1. How do we verify the equation of a line given two points?
  2. What are the coordinates of the midpoint of a segment in general?
  3. How do you derive the distance formula from the Pythagorean theorem?
  4. Can a line be parallel to the x- or y-axis? If so, how would the equation look?
  5. How does changing one point on a line affect its slope?

Tip: The distance formula is derived from the Pythagorean theorem and can be used to find the straight-line distance between any two points in a plane.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Equation of a Line
Midpoint Formula
Distance Formula

Formulas

Equation of a Line: y = mx + c
Midpoint Formula: M = ((x1 + x2)/2, (y1 + y2)/2)
Distance Formula: d = sqrt((x2 - x1)^2 + (y2 - y1)^2)

Theorems

-

Suitable Grade Level

Grades 9-11