algebra precalculus - Using unit circle to explain $\cos(0) = 1

We have been taught $\cos(0) = 1$ and $\sin(90) = 1$. But, how do I visualize these angles on the unit circle?

How to Find Exact Values of Cosine & Secant Using the Unit Circle & Special Triangles, Algebra

Solved e 2.1 Examine the first quadrant of the unit circle

Unit Circle

How do you find the exact value of sin(0)?

Unit circle (video), Trigonometry

PPT - The Unit Circle PowerPoint Presentation, free download - ID:2184628

5.2: Unit Circle - Sine and Cosine Functions - Mathematics LibreTexts

4-02 Unit Circle

Understanding the unit circle