Math Problem Statement

D: -2, 8 E: 2, 0 F: -2, -4

What is the area of triangle DEF with points D(-2, 8), E(2, 0), and F(-2, -4)?

Solution

We are given the coordinates of points D(2,8)D(-2, 8), E(2,0)E(2, 0), and F(2,4)F(-2, -4), and we need to find the area of triangle ΔDEF\Delta DEF.

The formula for 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|

Substituting the coordinates D(2,8)D(-2, 8), E(2,0)E(2, 0), and F(2,4)F(-2, -4) into this formula, we get:

Area=12(2)(0(4))+2((4)8)+(2)(80)\text{Area} = \frac{1}{2} \left| (-2)(0 - (-4)) + 2((-4) - 8) + (-2)(8 - 0) \right|

Let me calculate that for you.The area of triangle ΔDEF\Delta DEF is 2424 square units.

Do you want further details or have any questions?

Here are some related questions for practice:

  1. What is the perimeter of triangle ΔDEF\Delta DEF?
  2. Can you find the centroid (center of mass) of triangle ΔDEF\Delta DEF?
  3. How would the area change if point DD was shifted to (3,8)(-3, 8)?
  4. What is the slope of line DEDE in ΔDEF\Delta DEF?
  5. How can you use the distance formula to calculate the lengths of the sides of ΔDEF\Delta DEF?

Tip: When working with triangles on a coordinate plane, the formula for the area becomes much simpler when you know the vertices!

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Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Area of Triangles

Formulas

Area of a triangle = 1/2 * |x1(y2 - y3) + x2(y3 - y1) + x3(y1 - y2)|

Theorems

Area of Triangle using Vertices

Suitable Grade Level

Grades 8-10