A semicircular sheet of paper of radius 14 cm is rolled up so that its two straight radii meet, forming a cone. Find the curved surface area of the cone in ${\text{cm}}^2$. Take π = 22/7.

Rolling does not change the paper's area, so the curved surface of the cone equals the area of the semicircle = ½ × (22/7) × $14^2$ = ½ $\times 616=308{\text{cm}}^2$. (Its base radius is 7 cm, since the arc 14π must equal 2πr, so its total surface area would be $308+154=462{\text{cm}}^2$ — but only the curved part is asked for.)