WAEC - Mathematics (1993 - No. 15)
Calculate the total surface area of a cone of height 12cm and base radius 5cm. [Take π = 22/7]
180\(\frac{5}{7}\)cm\(^2\)
240\(\frac{2}{7}\)cm\(^2\)
235\(\frac{5}{7}\)cm\(^2\)
282\(\frac{6}{7}\)cm\(^2\)
361\(\frac{3}{7}\)cm\(^2\)
解释
πrl + πr2 = πr(l + r)
\(\frac{22}{7}\) x 5(13 + 5)
282\(\frac{6}{7}\)cm\(^2\)