Math Problem Statement

Answer the last one using graph

Find the equation of line AB and the area of triangle ABO using the graph provided.

Solution

Let's solve question 3 using the given graph for point C(3,4)C(3, 4), where we need to find:

  1. The equation of line AB\overline{AB}.
  2. The area of ABO\triangle ABO.

Step 1: Equation of line AB\overline{AB}

From the graph:

  • A(0,0)A(0, 0) is the origin.
  • B(6,0)B(6, 0) lies on the x-axis.

The equation of a straight line can be written as: y=mx+cy = mx + c where:

  • mm is the slope.
  • cc is the y-intercept.

Slope mm of AB\overline{AB}:

The slope between two points A(x1,y1)A(x_1, y_1) and B(x2,y2)B(x_2, y_2) is given by: m=y2y1x2x1m = \frac{y_2 - y_1}{x_2 - x_1} Substitute: m=0060=0m = \frac{0 - 0}{6 - 0} = 0

Since the slope m=0m = 0, line AB\overline{AB} is horizontal. The equation of a horizontal line is simply: y=cy = c Here, c=0c = 0, so: y=0y = 0

Thus, the equation of AB\overline{AB} is: y=0y = 0


Step 2: Area of ABO\triangle ABO

The vertices of ABO\triangle ABO are:

  • A(0,0)A(0, 0)
  • B(6,0)B(6, 0)
  • O(3,4)O(3, 4)

The area of a triangle given its vertices (x1,y1)(x_1, y_1), (x2,y2)(x_2, y_2), and (x3,y3)(x_3, y_3) is: Area=12x1(y2y3)+x2(y3y1)+x3(y1y2)\text{Area} = \frac{1}{2} \left| x_1(y_2 - y_3) + x_2(y_3 - y_1) + x_3(y_1 - y_2) \right|

Substitute the coordinates: x1=0,y1=0,x2=6,y2=0,x3=3,y3=4x_1 = 0, \, y_1 = 0, \, x_2 = 6, \, y_2 = 0, \, x_3 = 3, \, y_3 = 4

Area=120(04)+6(40)+3(00)\text{Area} = \frac{1}{2} \left| 0(0 - 4) + 6(4 - 0) + 3(0 - 0) \right| Area=120+24+0\text{Area} = \frac{1}{2} \left| 0 + 24 + 0 \right| Area=12×24=12\text{Area} = \frac{1}{2} \times 24 = 12

Thus, the area of ABO\triangle ABO is: 12square units\boxed{12 \, \text{square units}}


Final Answers:

  1. The equation of AB\overline{AB} is y=0\mathbf{y = 0}.
  2. The area of ABO\triangle ABO is 12square units\mathbf{12 \, \text{square units}}.

Would you like a deeper explanation of any step or further examples?

Follow-Up Questions:

  1. What is the general formula for the slope of a line?
  2. How do you calculate the area of a triangle using determinants?
  3. Can we find the length of side AB\overline{AB}? If yes, how?
  4. What happens if point OO moves? How does the area of the triangle change?
  5. Can you derive the equation of AB\overline{AB} if the slope is non-zero?

Tip:

Always double-check your slope and intercept calculations, as they directly influence the equation of the line.

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Math Problem Analysis

Mathematical Concepts

Analytical Geometry
Equation of a Line
Triangle Area Calculation

Formulas

Equation of a line: y = mx + c
Slope formula: m = (y2 - y1) / (x2 - x1)
Area of a triangle given vertices: (1/2) * |x1(y2 - y3) + x2(y3 - y1) + x3(y1 - y2)|

Theorems

Slope of a Line
Triangle Area Theorem

Suitable Grade Level

Grades 8-10