8. Coordinate Proofs
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Use the Distance Formula.
See solution.
Let's plot the points A, B, and C, and draw â–³ ABC.
| d = sqrt((x_2-x_1)^2 + (y_2-y_1)^2) | |||
|---|---|---|---|
| Side Length | Points | Substitute | Simplify |
| AB | A( 0,0) and B( 6,0) | AB=sqrt(( 6- 0)^2 + ( 0 - 0)^2) | AB=6 |
| AC | A( 0,0) and C( 3,3sqrt(3)) | AC=sqrt(( 3- 0)^2+( 3sqrt(3)- 0)^2) | AC=6 |
| BC | B( 6,0) and C( 3,3sqrt(3)) | BC=sqrt(( 3 - 6)^2+( 3sqrt(3)- 0)^2) | BC=6 |
Because all side lengths are equal, all three sides are congruent. Therefore, â–³ ABC is an equilateral triangle.