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?

The Unit Circle CK-12 Foundation

4.1.4: The Unit Circle - Mathematics LibreTexts

3.4 Sine and cosine function graphs, AP Precalculus Math, AP Precalculus (BETA)

Solved Precalculus Module 7: Investigation 4 Using Sine and

In Exercises 25–32, the unit circle has been divided into eight e

4.1.4: The Unit Circle - Mathematics LibreTexts

Unit circle (video), Trigonometry