High School

Which statement justifies the given reasons in the geometric proof below?

1. PR bisects ∠QPS.
2. ∠QPR is congruent to ∠RPS.
3. ∠QPS is a right angle.
4. ∠QPS measures ___ degrees.
5. ∠QPR measures ___ degrees and ∠RPS measures ___ degrees, adding up to the measure of ∠QPS.
6. ∠QPR and ∠RPS together form a total of ___ degrees.
7. Doubling the measure of ∠RPS gives a total of 90°.
8. Therefore, the measure of ∠RPS is ___ degrees.

a) Definition of a Right Angle
b) Angle Addition Postulate
c) Segment Addition Postulate
d) Distributive Property

Answer :

Final answer:

The statement that justifies the given reasons in the geometric proof is the Angle Addition Postulate. The proof uses the facts that PR bisects ∠QPS, ∠QPR is congruent to ∠RPS, ∠QPS is a right angle, ∠QPS measures 90 degrees, ∠QPR measures 45 degrees, ∠RPS measures 45 degrees, doubling the measure of ∠RPS gives a total of 90 degrees, and therefore the measure of ∠RPS is 45 degrees.

Explanation:

The statement that justifies the given reasons in the geometric proof is b) Angle Addition Postulate.

PR bisects ∠QPS: This means that the angle ∠QPS is divided into two congruent angles, ∠QPR and ∠RPS.

∠QPR is congruent to ∠RPS: Since PR bisects ∠QPS, ∠QPR and ∠RPS are congruent by definition.

∠QPS is a right angle: This is given in the proof.

∠QPS measures 90 degrees: This is given in the proof.

∠QPR measures 45 degrees and ∠RPS measures 45 degrees: Since ∠QPR and ∠RPS are congruent and their measures add up to the measure of ∠QPS, each angle measures half of 90 degrees, which is 45 degrees.

∠QPR and ∠RPS together form a total of 90 degrees: This is simply the fact that their measures add up to 90 degrees.

Double the measure of ∠RPS gives a total of 90 degrees: This is given in the proof.

Therefore, the measure of ∠RPS is 45 degrees: By doubling the measure of ∠RPS, we get 90 degrees and since the measure of ∠RPS and ∠QPR are equal, each angle measures 45 degrees.