Big Ideas Math Integrated I, 2016
BI
Big Ideas Math Integrated I, 2016 View details
Chapter Test
Continue to next subchapter

Exercise 10 Page 651

Begin by labeling the vertices with their coordinates.

See solution.

Practice makes perfect

Let's mark the coordinates of the unlabeled vertices.

There are a couple of theorems we can use to prove congruence.
  1. We can use the SSS Congruence Theorem. This requires us to calculate all sides of the triangles.
  2. We can also use the SAS Congruence Theorem if we recognize that ∠ TRS and ∠ QRP are vertical angles and therefore congruent.

Since SAS only requires us to calculate two sides in each of the triangles, we will use this theorem.

Side Points sqrt((x_2-x_1)^2+(y_2-y_1)^2) d
PR ( 12,15), ( 3,30) sqrt(( 12- 3)^2+( 15- 30)^2) sqrt(306)
RQ ( 21,30), ( 12,15) sqrt(( 21- 12)^2+( 30- 15)^2) sqrt(306)
TR ( 12,15), ( 3,0) sqrt(( 12- 3)^2+( 15- 0)^2) sqrt(306)
SR ( 21,0), ( 12,15) sqrt(( 21- 12)^2+( 0- 15)^2) sqrt(306)

Both triangles are isosceles triangles with congruent legs. As we already stated, the included angle of the triangles legs are vertical angles and therefore congruent. Therefore, we can by the SAS Congruence Theorem claim that the triangles are congruent.