Original: For example, if the angle between the road and the uphill direction, projected onto the horizontal plane, is 60 Â, then the steepest slope along the road will be 20%, which is 40% times the cosine of 60 Â.
Simplified: For example, if the angle between the road and the uphill direction, projected onto the horizontal plane, is 60 Â, then the steepest slope along the road will be 20% which is 40% times the cosine of 60 Â.