A hemispherical depression of diameter 4 cm is cut out from each face of a cubical block of sides 10cm. Find the surface area of the remaining solid (in cm2).
( Use π =22/7)
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 675
Given:
Each face of a cubical block of sides 10 cm
radius of hemispherical depression = 4 cm
Formula used:
Area of circle = πr2
Total surface area of cube = 6a2
Curved surface area of hemisphere = 2πr2
Calculations:
According to the figure we have
Required area = TSA of cube - 6 × area of circle + 6 × CSA of hemisphere
⇒ 6 × 102 - 6 × πr2 + 6 × 2πr2
⇒ 600 + 6 × π × 22
⇒ 600 + 75(3/7) = 675(3/7)