In Fig., from a cuboidal solid metallic block, of dimensions 15 cm ×

1.	In Fig., from a cuboidal solid metallic block, of dimensions 15 cm × 10 cm × 5 cm, a cylindrical hole of diameter 7 cm is drilled out. Find the surface area of the remaining block.(Take π = \(\frac{22}7\))
Answer» Here, dimension of cuboid = 15 cm × 10 cm × 5 cm Radius of cylindrical hole = \(\frac{7}2\) cm Surface area of the remaining block = surface area of cuboidal solid metallic block – 2 × base area of cylindrical hole = 2(15 × 10 + 10 × 5 + 5 × 15) - 2 × \(\frac{22}7\times(\frac{7}2)^2\) = 583 cm²

In Fig., from a cuboidal solid metallic block, of dimensions 15 cm × 10 cm × 5 cm, a cylindrical hole of diameter 7 cm is drilled out. Find the surface area of the remaining block.(Take π = \(\frac{22}7\))

Answer»

Here,

dimension of cuboid = 15 cm × 10 cm × 5 cm

Radius of cylindrical hole = \(\frac{7}2\) cm

Surface area of the remaining block = surface area of cuboidal solid metallic block – 2 × base area of cylindrical hole

= 2(15 × 10 + 10 × 5 + 5 × 15) - 2 × \(\frac{22}7\times(\frac{7}2)^2\)

= 583 cm²