The Tangent Ratio

The sun's ray climbed 15.07 m over 20 m of shadow. That is about 0.75 m up for every metre along. A road sign that says 12% means 12 m up for every 100 m along. That is only 0.12 m up per metre. So the ray is much steeper.

The height up divided by the distance along is the tangent. In a triangle it is opposite divided by adjacent: $\tan\left(\theta\right) = \frac{opposite}{adjacent}$. One side divided by another is called a ratio. At 45° the height and the distance are equal, so $\tan\left(45^{\circ}\right) = 1$. Above 45°, the tangent is more than 1.