Question

1. what does james need to justify this statement in a proof.

because ∠a = 90° then ∠a is a right angle.
definition of right angles
syllogisms
symmetric property
definition of angle measure

Explanation:

A right - angle is defined as an angle that measures \(90^{\circ}\). Since the statement says that because \(\angle A = 90^{\circ}\), then \(\angle A\) is a right angle, it directly uses the definition of right angles.
Syllogisms are a form of logical reasoning with a major premise, minor premise, and conclusion. This is not a syllogism. The symmetric property is about equality relations (if \(a = b\), then \(b=a\)) and is not relevant here. The definition of angle measure is a more general concept about how angles are measured (e.g., in degrees) and does not specifically justify the connection between a \(90^{\circ}\) angle and being a right angle.

Answer:

Definition of Right Angles