Geometry

Question Analysis  

Determine the coordinates of a point on the unit circle for a 45° angle in Quadrant I.  

Key Concept Explanation  

Unit Circle Definition: For any angle θ, the point on the unit circle is .  

45-45-90 Triangle: In Quadrant I, a 45° angle forms an isosceles right triangle with equal legs () and hypotenuse 1 (unit circle).  

Step-by-Step Solution  

1. On the unit circle, the -coordinate =  and -coordinate = .  

2. For θ = 45°, .  

3. Thus, the point is .  

Option Analysis  

A:  Correct (follows unit circle definition).  

B:

Click "Show Answer" to reveal the answer and analysis