Geometry

Question Analysis  

Determine the angle in Quadrant I where on the unit circle, leveraging the symmetry of 45-45-90 triangles.  

 

Key Concept Explanation  

On the unit circle, and .  

For , , which occurs only when (45-45-90 triangle with equal legs).  

 

Step-by-Step Solution  

1. Since , .  

2. This implies .  

3. The only angle in Quadrant I with is .  

 

Option Analysis  

30°: Incorrect (, ,