Short Answer 
The cloud ceiling refers to the height from the ground to the lowest cloud layer, measured at 0.273 km. By using a right-angle triangle and the tangent function, the calculation confirms this distance, emphasizing its relevance for meteorology and aviation safety.
Step 1: Understanding Cloud Ceiling
The cloud ceiling is defined as the distance between the ground and the lowest cloud layer. In this case, we are looking at a specific measurement of 0.273 km from the ground to that cloud layer. It’s essential to know this distance for various meteorological applications and safety in aviation.
Step 2: Utilizing the Right Triangle
To determine the cloud ceiling, we can visualize the situation using a right-angle triangle. The tangent function relates the angle of elevation to the opposite and adjacent sides of this triangle. Recall the formula: tan θ = opposite/adjacent. This method allows us to calculate the vertical height of the cloud ceiling based on a known distance.
Step 3: Calculation of the Cloud Ceiling
Using the information gathered, we apply the tangent value to find the lowest cloud height. By using the tangent value of tan(20°) = 0.75 km, we set up our equation: XY = 0.36397 × 0.75 km. Performing the calculation gives us XY = 0.273 km, confirming that the cloud ceiling is at this distance from the ground.