A square-shaped piece of metal has a circular hole cut out exactly from its center, touching all four sides. What percentage of the metal sheet's area remains after the hole is cut? (Use π≈3.14)
Show answer & explanation
Correct answer: A
Explanation
Side of square = a
Radius of circle = a/2
Area of circle = πa²/4
Remainder = a² − πa²/4 = a²(1 − π/4)
% Remainder = (1 − 3.14/4) × 100
= (1 − 0.785) × 100
= 21.5%