1
28. From a cubical piece of wood of side 21 cm, a hemisphere is carved out
in such a way that the diameter of the hemisphere is equal to the side of
the cubical piece. Find the surface area and volume of the remaining
piece.
[CBSE 2014
2
Answers
Answered by
2
Answer:
side of cube(a) = 21
radius of hemisphere (r) = 21/2
Step-by-step explanation:
volm of cube = a³
volm of hemisphere = ⅔πr³
required volm = a³ - ⅔πr³
= 21³ - ⅔ ×22/7 × (21/2)³
= 9261 - 2425.5
= 6835.5 cm³
surface area = 5a² + 2πr²
= 5×(21)² + 2× 22/7 × (21/2)²
= 2205 + 693
= 2898 cm²
Similar questions