Question

To the nearest tenth, find the perimeter of ∆ABC with vertices A(2,4), B(-2,1) and C(2,1). Show your work.

Answer 1

1. draw an accurate picture of the triangle in the coordinate axes.

2. The distance BC is 4 (both B and C have equal y coordinate so we subtract the x coordinates)

the distance AC is 3, (both A and C have same x coordinate)

3. The triangle is a right triangle since BC is parallel to the x-axis, and AC is parallel to the y-axis, which means the angle between BC and AC is 90.

4. AB is 5 units, by the special right triangle 3-4-5 (a result of the Pythagorean theorem)

5. Perimeter of ABC= 3+4+5=7+5=12 units

Answer: 12 units