What is the percentage of subgrade slope 1: 1.5? But will the following link 150% in Baidu be an expression of 1: 1.5?

In the construction of municipal water conservancy houses, roads and bridges, there are three manifestations in places with slopes:

1, the slope, that is, 1: 1.5 becomes 66.66%.

2. The slope ratio is 1: 1.5.

3. The inclination angle is 1: 1.5, and the angle is 33.69 degrees.

These three algorithms are actually the same algorithm: height difference and horizontal distance, but their expressions are different.

Just like when I was a child, I can change it into fractions, decimals and percentages.