Math Problem Statement

Line $\ell$ is drawn in the coordinate plane below. If the slope of line $\ell$ is $3,$ then find the area of the triangle determined by the line and the coordinate axes.

[asy] unitsize(1 cm);

pair A, B, O, P;

A = (2,0); B = (0,-3); O = (0,0); P = (O + reflect(A,B)*(O))/2;

draw(interp(A,B,-0.2)--interp(A,B,1.2), blue); draw((-1,0)--(3,0)); draw((0,-4)--(0,1)); draw(O--P); draw(rightanglemark(O,P,B,5));

label("$x$", (3,0), E); label("$y$", (0,1), N); label("$\ell$", interp(A,B,-0.2), N); label("$2$", (O + P)/2, SW, red); [/asy]

Solution

To find the area of the triangle formed by the line \ell and the coordinate axes, we start by analyzing the given slope and determining the points where the line intersects the axes.

Step 1: Interpret the Slope and Formulate the Line Equation

The problem states that the slope of line \ell is 33. Therefore, we know: slope=3\text{slope} = 3 The general equation for a line with slope mm is: y=mx+by = mx + b Since the slope m=3m = 3, we have: y=3x+by = 3x + b To find the yy-intercept bb, we use the fact that the line passes through the point (2,0)(2, 0) as shown in the figure.

Step 2: Substitute the Point (2,0)(2, 0) to Find bb

Substitute x=2x = 2 and y=0y = 0 into the line equation: 0=3(2)+b0 = 3(2) + b 0=6+b0 = 6 + b b=6b = -6 Thus, the equation of line \ell is: y=3x6y = 3x - 6

Step 3: Find the Intercepts

To find the points where the line intersects the xx- and yy-axes, set y=0y = 0 for the xx-intercept and x=0x = 0 for the yy-intercept.

xx-Intercept

Set y=0y = 0: 0=3x60 = 3x - 6 3x=63x = 6 x=2x = 2 So, the xx-intercept is (2,0)(2, 0).

yy-Intercept

Set x=0x = 0: y=3(0)6y = 3(0) - 6 y=6y = -6 So, the yy-intercept is (0,6)(0, -6).

Step 4: Calculate the Area of the Triangle

The triangle formed by the line and the coordinate axes has vertices at (0,0)(0, 0), (2,0)(2, 0), and (0,6)(0, -6).

The base of the triangle is the distance along the xx-axis from (0,0)(0, 0) to (2,0)(2, 0), which is 22 units.

The height of the triangle is the distance along the yy-axis from (0,0)(0, 0) to (0,6)(0, -6), which is 66 units.

The area AA of a triangle is given by: A=12×base×heightA = \frac{1}{2} \times \text{base} \times \text{height} Substitute the values for the base and height: A=12×2×6=12×12=6A = \frac{1}{2} \times 2 \times 6 = \frac{1}{2} \times 12 = 6

Conclusion

The area of the triangle formed by the line and the coordinate axes is: 6\boxed{6}

Would you like a breakdown of any steps or additional details?

Here are some related questions you might find interesting:

  1. How do you find the equation of a line given two points?
  2. What is the formula for the area of a triangle with vertices at specific points?
  3. How does changing the slope affect the intercepts of a line?
  4. How can you determine the area of a shape bounded by a line and the axes in the coordinate plane?
  5. What happens to the area of the triangle if the slope changes but the intercept remains fixed?

Tip: Knowing how to find intercepts quickly helps in determining areas of shapes in the coordinate plane!

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Math Problem Analysis

Mathematical Concepts

Slope of a line
Coordinate geometry
Area of a triangle

Formulas

Area of a triangle = 1/2 × base × height

Theorems

Slope-intercept form of a line
Intercepts of a line

Suitable Grade Level

Grades 9-10