Surface area of the doubled cone = (Curved surface area of cone CAA’)

+ (Curved surface area of cone BAA’)

= (OA×AC) + (OA×AB)

= (12×20) + (12×15) cm²

= 420 cm²

= 420 × 22/7 cm ²

= 1320 cm²

A wooden toy rocket is in the shape of a cone mounted on a cylinder as shown in the adjacent figure. The height of the entire rocket is 26 cm, while the height of the conical part is 6cm. The base of the conical position has a diameter of 5 cm, while the base diameter of the cylindrical portion is 3 cm. If the conical portion is to be painted orange and the cylindrical portion is to be painted yellow, find the area of the rocket painted with each of these color (Take = 3.14)

Let ‘r’ be the radius of the base of the cone and its slant height be ‘l’. Further, let r₁ be the radius of cylinder and h₁ be its height

We have,
r = 2.5 cm., h = 6 cm.
r₁ = 1.5 cm. h₁ = 20 cm.

Now, area to be painted in orange =

CSA of the cone + base area of the cone - base area of the cylinder 3 cm

= πrl + πr² - πr₁²

= π{(2.5×2.6) + (2.5)² - 1.5²cm²}

= π(20.25)cm² = 3.14 × 20.25 cm² = 63.585cm²

Area to be painted yellow

= Curved surface area of the cylinder + Area of the base of the cylinder

= 2πr₁h₁ + πr₁²
= π₁(2h₁ + r₁)