Since, the given right angled triangle is revolved about the side 8 cm, it will form a Cone of radius 6cm and height 8cm. Volume of a cone = 1/3∏r2h = 1/3×3.14×6×6×8 = 301.44 cm3 Curved Surface area of a cone =∏rl .... (i) We know that, l2 = r2 + h2 = 62 + 82 = 36 + 64 = 100 → l = 10 cm Substitute the value of l in (i), we get Curved Surface area of a cone = 3.14 × 6 × 10 = 188.4 cm2