Math Problem Statement

Consider A(-3;-4), B(1;2) and C(4;-3).

1° Determine an equation of the height drawn from C in triangle ABC.

2º Determine an equation of the perpendicular bisector of segment [AB].

Solution

Problem Breakdown:

We are given three points:
A(3,4)A(-3, -4), B(1,2)B(1, 2), and C(4,3)C(4, -3).

  1. Determine the equation of the height drawn from CC:
    The height from CC in ABC\triangle ABC is a line that passes through CC and is perpendicular to the side ABAB.

  2. Determine the equation of the perpendicular bisector of segment [AB][AB]:
    The perpendicular bisector is a line that is perpendicular to ABAB and passes through its midpoint.


1. Height from CC:

Step 1. Find the slope of ABAB:

The slope formula is:
m=y2y1x2x1.m = \frac{y_2 - y_1}{x_2 - x_1}.
Substituting A(3,4)A(-3, -4) and B(1,2)B(1, 2):
mAB=2(4)1(3)=64=32.m_{AB} = \frac{2 - (-4)}{1 - (-3)} = \frac{6}{4} = \frac{3}{2}.

Step 2. Find the slope of the height:

The height from CC is perpendicular to ABAB, so its slope is the negative reciprocal of mABm_{AB}:
mheight=1mAB=132=23.m_{\text{height}} = -\frac{1}{m_{AB}} = -\frac{1}{\frac{3}{2}} = -\frac{2}{3}.

Step 3. Write the equation of the height:

The equation of a line is given by:
yy1=m(xx1),y - y_1 = m(x - x_1),
where (x1,y1)=(4,3)(x_1, y_1) = (4, -3) and m=23m = -\frac{2}{3}:
y(3)=23(x4).y - (-3) = -\frac{2}{3}(x - 4).
Simplify:
y+3=23x+83.y + 3 = -\frac{2}{3}x + \frac{8}{3}.
y=23x+833.y = -\frac{2}{3}x + \frac{8}{3} - 3.
y=23x13.y = -\frac{2}{3}x - \frac{1}{3}.

The equation of the height is:
y=23x13.y = -\frac{2}{3}x - \frac{1}{3}.


2. Perpendicular Bisector of [AB][AB]:

Step 1. Find the midpoint of ABAB:

The midpoint formula is:
M=(x1+x22,y1+y22).M = \left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right).
Substituting A(3,4)A(-3, -4) and B(1,2)B(1, 2):
M=(3+12,4+22)=(1,1).M = \left( \frac{-3 + 1}{2}, \frac{-4 + 2}{2} \right) = \left( -1, -1 \right).

Step 2. Find the slope of the perpendicular bisector:

The slope of ABAB is 32\frac{3}{2}, so the slope of the perpendicular bisector is the negative reciprocal:
mbisector=1mAB=23.m_{\text{bisector}} = -\frac{1}{m_{AB}} = -\frac{2}{3}.

Step 3. Write the equation of the perpendicular bisector:

Using the point-slope form yy1=m(xx1)y - y_1 = m(x - x_1), where (x1,y1)=(1,1)(x_1, y_1) = (-1, -1) and m=23m = -\frac{2}{3}:
y(1)=23(x(1)).y - (-1) = -\frac{2}{3}(x - (-1)).
Simplify:
y+1=23(x+1).y + 1 = -\frac{2}{3}(x + 1).
y+1=23x23.y + 1 = -\frac{2}{3}x - \frac{2}{3}.
y=23x231.y = -\frac{2}{3}x - \frac{2}{3} - 1.
y=23x53.y = -\frac{2}{3}x - \frac{5}{3}.

The equation of the perpendicular bisector is:
y=23x53.y = -\frac{2}{3}x - \frac{5}{3}.


Summary of Results:

  1. Equation of the height from CC:
    y=23x13.y = -\frac{2}{3}x - \frac{1}{3}.
  2. Equation of the perpendicular bisector of [AB][AB]:
    y=23x53.y = -\frac{2}{3}x - \frac{5}{3}.

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Related Questions:

  1. What is the equation of the side ABAB in the triangle?
  2. How do you find the coordinates of the centroid of ABC\triangle ABC?
  3. What are the slopes of the other two heights in ABC\triangle ABC?
  4. Can you calculate the area of ABC\triangle ABC?
  5. How do you find the circumcenter of ABC\triangle ABC?

Tip:

Always verify perpendicularity by checking if the product of two slopes is 1-1.

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Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Lines and Slopes
Perpendicular Lines
Midpoint Formula

Formulas

Slope formula: m = (y2 - y1) / (x2 - x1)
Point-slope form: y - y1 = m(x - x1)
Midpoint formula: M = ((x1 + x2) / 2, (y1 + y2) / 2)

Theorems

The slope of perpendicular lines is the negative reciprocal of each other.

Suitable Grade Level

Grades 9-11