Verify that D(3, 7) is a midpoint of AC.
Write the equation of the line through points D and B.
Is BD a height of ΔABC? Use slope to show that BD is perpendicular to AC.
What is the perimeter and area of ΔABC?
To find the midpoint between two points (average x-coordinates, average y-coordinates).
Read Math Notes box in Lesson 2.3.2 on linear equations from slopes and/or points.
Calculate the slope between points D and B.
Using the slope, the x- and y-coordinates from point D or B, and slope intercept form (y = mx + b). Solve for b.
Compare the slopes of segment BD and segment AC. What do you notice?
Use the Pythagorean Theorem to find the length of all missing sides.
Perimeter ≈ 20.467 units, Area = 20 units²
Use the eTool below to solve the problem.
Click the link at right for the full version of the eTool: Int1 8-28 HW eTool