Explanation:
Figure A:
Square has side 12 units
Area of square = s² = (12 units)² = 144 units²
Circle has diameter 12 units; radius 6 units
Area of one circle = πr² = π × (6 units)² = 36π units²
Total circle area = 1 × 36π units² = 36π units²
Shaded area = (144 - 36π) units²
Figure B:
Square has side 12 units
Area of square = s² = (12 units)² = 144 units²
Circle has diameter 6 units; radius 3 units
Area of one circle = πr² = π × (3 units)² = 9π units²
Total circle area = 4 × 9π units² = 36π units²
Shaded area = (144 - 36π) units²
Figure C:
Square has side 12 units
Area of square = s² = (12 units)² = 144 units²
Circle has diameter 4 units; radius 2 units
Area of one circle = πr² = π × (2 units)² = 4π units²
Total circle area = 9 × 4π units² = 36π units²
Shaded area = (144 - 36π) units²