In figure, from a cuboidal solid metallic block of dimensions 15 cm x 10 cm x 5 cm, a cylindrical hole of diameter 7 cm is drilled out. Find the surface area of the remaining block.
[Use π = 22/7]
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Surface area of the remaining block = 583 sq. cm
Step-by-step explanation:
Length of cube = 15 cm
Breadth of cube = 10 cm
Height of cube = 5 cm
Height of cylinder = 5 cm
Radius of cylinder = 7/2 cm
Surface area of cuboid = 2(lb + bh + hl) = 2 * (15*10 + 10*5 + 5*15) = 550 sq. cm
2* Area of cylindrical hole = 2πr² = 2 * 22/7 * 7/2 * 7/2 = 77 sq. cm
Surface area of cylinder = 2πrh = 2 * 22/7 * 7/2 * 5 = 110 sq. cm
Surface area of the remaining block = Surface area of the cuboid + Surface area of cylinder - 2 * Area of cylindrical hole
= 550 + 110 - 77
= 583 sq. cm
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