Finding the Equation of a Perpendicular Line Given the Area of the Triangle Formed

Introduction to Perpendicular Lines and Calculating the Area of the Triangle Formed

In this article, we will explore the methods for finding the equation of a line perpendicular to a given line, and then derive the specific equations when the area of the triangle formed by this line with the coordinate axes is given.

Step-by-Step Solution

Let's begin with the given line equation: (3x - 2y - 4 0).

Step 1: Determine the Slope of the Given Line

The equation can be rearranged into the slope-intercept form (y mx b).

(3x - 2y - 4 0 implies -2y -3x - 4 implies y frac{3}{2}x - 2)

The slope of the given line, (m_1), is (frac{3}{2}).

Step 2: Determine the Slope of the Perpendicular Line

Since the lines are perpendicular, the slope of the new line, (m_2), is the negative reciprocal of (m_1).

(m_2 -frac{2}{3})

Step 3: Equation of the Perpendicular Line

The equation of the line (l) in point-slope form, passing through the origin, is:

(y -frac{2}{3}x)

However, we need to find where this line intersects the coordinate axes to form a triangle with an area of 27 square units.

Step 4: Finding the X- and Y-Intercepts

To find the x-intercept, set (y 0):

(0 -frac{2}{3}x implies x 0)

To find the y-intercept, set (x 0):

(y -frac{2}{3}(0) implies y 0)

These intercepts alone do not form a triangle with area 27, so we need a more general form.

Step 5: General Equation of the Perpendicular Line

Let's express the equation of line (l) in the form (y -frac{2}{3}x c), where (c) is the y-intercept.

To find the x-intercept, set (y 0):

(0 -frac{2}{3}x c implies x frac{3c}{2})

To find the y-intercept, set (x 0):

(y c)

Step 6: Area of the Triangle

The area (A) of the triangle formed by the intercepts on the axes is given by:

(A frac{1}{2} times text{X-intercept} times text{Y-intercept} frac{1}{2} times frac{3c}{2} times c frac{3c^2}{4})

Setting this area equal to 27:

(frac{3c^2}{4} 27)

Step 7: Solve for (c)

Multiply both sides by 4:

(3c^2 108 implies c^2 36 implies c 6 text{ or } c -6)

Step 8: Form the Equations of Line (l)

Using (c 6):

(y -frac{2}{3}x 6)

Using (c -6):

(y -frac{2}{3}x - 6)

Conclusion

The equations of the line (l) are:

(boxed{y -frac{2}{3}x 6}) and (boxed{y -frac{2}{3}x - 6})