A hemispherical depression of diameter 4 cm is cut out from each face of a cubical block of sides 10 cm. Find the surface area of the remaining solid (in cm²)

(Use π=$\frac{22}{7}$)

$675\frac{3}{7}$

We know that,

TSA of the cube = 6a²

CSA of the hemisphere = 2πr²

Area of a circle = πr²

We have,

Diameter of the hemispherical depression = 4 cm

Each face of the cube = 10 cm

Then the radius of hemisphere = 5

Required surface area = TSA of the cube - 6 × areas of circle form on the top of each face of the cube + 6 × CSA of hemisphere formed on each face of a cube

= 6 × 10² - 6 × π2² + 6 × 2π2²

= 600 + 6π2²

= 600 + 24 × \(\frac{22}{7}\) = 600 + \(\frac{528}{7}\) = $675\frac{3}{7}$