Q. 324.7( 12 Votes )

# A wooden toy is i

Answer :

The wooden toy is in the shape of a cone mounted on a cylinder

Total height of the toy = 26 cm

Height of conical part = H = 6 cm

Height of cylindrical part = Total height of the toy – Height of conical part

h = 26 cm – 6 cm = 20 cm

Diameter of conical part = 5 cm

Radius of conical part = R = Diameter/2 = 5/2 cm = 2.5 cm

Let L be the slant height of the cone

L2 = H2 + R2

L2 = 62 + 2.52 cm2 = 36 + 6.25 cm2 = 42.25 cm2

L = 6.5 cm

Diameter of cylindrical part = 4 cm

Radius of cylindrical part = r = Diameter/2 = 4/2 cm = 2 cm

Area to be painted Red = Curved Surface area of cone + Base area of cone – base area of cylinder

Area to be painted Red = πRL + πR2 – πr2 = π (RL + R2 – r2)

= 22/7 × (2.5 × 6.5 + 2.5 × 2.5 – 2 × 2) cm2

= 22/7 × (16.25 + 6.25 – 4) cm2

= 22/7 × 18.5 cm2

= 58.143 cm2

Area to be painted White = Curved Surface area of cylinder + Base area of cylinder

Area to be painted White = 2πrh + πr2 = πr (2h + r)

= 22/7 × 2 × (2 × 20 + 2) cm2

= 22/7 × 2 × (40 + 2) cm2

= 22/7 × 2 × 42 cm2 = 264 cm2

Area to be painted red is 58.143 cm2 and area to be painted white is 264 cm2.

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