NCERT Exemplar Solutions
Class 7 - Mathematics - Unit 9: Perimeter and Area - Problems and SolutionsQuestion 131
Class 7 - Mathematics - Unit 9: Perimeter and Area - Problems and Solutions
Question. 131
A photograph of Billiard/Snooker table has dimensions as \(\tfrac{1}{10}\)th of its actual size as shown in Fig. 9.71: The portion excluding six holes each of diameter 0.5 cm needs to be polished at rate of ₹200 per m². Find the cost of polishing.
Answer:
Cost of polishing = ₹50.
Detailed Answer with Explanation:
Area of rectangle = 25 × 10 = 250 cm². 6 holes area = 6 × π × (0.25)² ≈ 1.18. Net area = 248.82 cm² = 0.024882 m². Cost = 0.024882 × 200 ≈ ₹50.