Multiple choice A pipe is of 5 cm radius and 10 cm height. Calculate its cross sectional area. $314.159\ cm^2$ $78.53\ cm^2$ $11.625\ cm^2$ None of the above Reveal answer Fill a bubble to check yourself B Correct answer Explanation Cross-sectional area of a cylinder is the area of its circular base, pi * r^2. Area = 3.14159 * 5^2 = 3.14159 * 25 = 78.53975.