From a solid right circular cylinder of a height 2.4cm and radius 0.7cm, a right circular cone of same height and same radius is cut. Find the total surface area of the remaining solid.

For both Cylinder and Cone : h=2.4cm, r=0.7cm
Total surface area of remaining solid = Total surface area of cylinder - Total surface area of cone (a)
Total surface area of cylinder = 2πr(r+h) = 2π × 7/10 × (7/10 + 24/10) = 14π × 31/100 (1)
Total surface area of cone = πr(r+l) = π × 7/10(7/10 + √h² + r²) = π × 7/10(7/10 + √(24/10)² + (7/10)²) = 7π/10(7/10 + √576/100 + 49/100) = 7π/10(7/10 + √625/100) = 7π/10(7/10 + 25/10) = 7π/10 × 32/10 .. (2)
Substituting (1) and (2) in (a), We get,
Total surface area of remaining solid = π(434/100 - 224/100)
Total surface area of remaining solid = 6.6cm²