Babylonian trigonometry "simpler, more accurate... has clear advantages over our own."

[DetlefK]

3. Sounds to me like they used the next-more-complicated version of fractional numbers.

"Our research reveals that Plimpton 322 describes the shapes of right-angle triangles using a novel kind of trigonometry based on ratios, not angles and circles. It is a fascinating mathematical work that demonstrates undoubted genius.

In a fractional number, you give the ratio a:b

I guess, the babylonian trigonometry was based on a system of ratios a:b:c

And, just to be clear on this, our trigonometry is also based on ratios.
Sine and Cosine are both defined as ratios.
The equation sin² + cos² = 1 is exactly the same as the equation a²+b²=c²