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?

4-02 Unit Circle

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This Unit Circle Poster : r/PenmanshipPorn

4-02 Unit Circle

What is a Unit Circle?

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