Multiple choice

A solid is in the form of a right circular cylinder with hemispherical ends. The total length of the solid is 35 cm. The diameter of the cylinder is 1/4th of its height. Find the surface area of the solid.

  1. 680 sq. cm

  2. 800 sq. cm

  3. 770 sq. cm

  4. 720 sq. cm

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total length = cylinder height + 2 × radius = 35 cm. Given diameter = height/4, so 2r = h/4, meaning h = 8r. Therefore: 8r + 2r = 35, so 10r = 35 and r = 3.5 cm. Height h = 28 cm. Surface area = curved surface of cylinder + surface of sphere = 2πrh + 4πr² = 2π × 3.5 × 28 + 4π × 3.5² = 196π + 49π = 245π ≈ 770 sq. cm.

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