Diameter, d = 10.5cm
Radius, r = \(\frac{10.5}{2}\) cm = 5.25 cm
Slant height, l = 10 cm
Curved surface area = \(\pi rl\)
\(= \frac{22}{7} × 5.25 × 10\)
= 165 cm²
Thus, curved surface area of the cone = 165 cm².
In Fig. 9.26, A, B, C and D are four points on a circle. AC and BD intersect at a point E such that ∠ BEC = 130° and ∠ ECD = 20°. Find ∠ BAC.