Multiple choice

The total surface area of the cylindrical iron pillar surmounted by a cone of radius and height equal to that of the cylinder (r = 6 cm, h = 8 cm) is

  1. $ \displaystyle 190 \pi cm^{2} $
  2. $ \displaystyle 192 \pi cm^{2} $
  3. $ \displaystyle 195 \pi cm^{2} $
  4. $ \displaystyle 198 \pi cm^{2} $
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Surface area = Cylinder lateral area + Base area + Cone lateral area. Cylinder lateral = 2 * pi * r * h = 2 * pi * 6 * 8 = 96 pi. Base = pi * r^2 = 36 pi. Cone lateral = pi * r * l, where l = sqrt(r^2 + h^2) = 10. Cone lateral = pi * 6 * 10 = 60 pi. Total = 96 pi + 36 pi + 60 pi = 192 pi.

Keep practicing — related questions