Geometry

Question Analysis:
This question applies syllogistic reasoning within the context of scalene triangle properties.
The main focus is on using the definition of a scalene triangle and the relationship between side - length and angle - measure to draw a conclusion about triangle DEF.

Key Concept Explanation:
The first statement defines a scalene triangle in terms of side - length.
The second statement shows the connection between side - length and angle - measure for such a triangle.

Step - by - Step Solution:
Given:
Premise 1: If a triangle is scalene, then all its sides have different lengths.
Premise 2: If all sides of a triangle have different lengths, then all its angles have different measures.
Premise 3: Triangle DEF is scalene.
Since triangle DEF is scalene (Premise 3), by Premise 1, all its sides have different lengths.
Then, because all its sides have different lengths, by Premise 2, all its angles have different measures.

Option Analysis:
Option A: As per the step - by - step solution, all angles of triangle DEF have different measures, so th...