CBSE Class 5 Mathematics Area And Its Boundary Worksheet Set 04

Question a) i. Find the area of the floor of a room to carpet whose length is 12m and breadth is 9m
Answer: Length of the room = 12 m
Breadth of the room = 9 m
Area of the rectangular floor = Length \(\times\) Breadth
Area = \(12 \text{ m} \times 9 \text{ m} = 108 \text{ sq. m}\)
In simple words: Multiply the length and breadth of the room to find its total floor area.
Exam Tip: Always include the correct square units (like sq. m or \(\text{m}^2\)) when calculating area.

Question a) ii. What will be the cost of the carpet if sq. m costs Rs50?
Answer: Total area of the room = 108 sq. m
Cost of carpeting 1 sq. m = Rs. 50
Total cost of the carpet = Total area \(\times\) Cost per sq. m
Total cost = \(108 \times 50 = \text{Rs. } 5400\)
In simple words: Multiply the total area by the cost of one square meter to get the final price.

Exam Tip: Double-check your multiplication and make sure to write the currency symbol (Rs.) in your final answer.

Question b. Find the cost of fencing a Rectangular park of 120m length and 80m breadth at the rate of Rs.2 per metre.
Answer: Length of the rectangular park = 120 m
Breadth of the rectangular park = 80 m
Perimeter of the park = \(2 \times (\text{Length} + \text{Breadth})\)
Perimeter = \(2 \times (120 + 80)\)
Perimeter = \(2 \times 200 = 400 \text{ m}\)
Rate of fencing = Rs. 2 per metre
Total cost of fencing = Perimeter \(\times\) Rate per metre
Total cost = \(400 \times 2 = \text{Rs. } 800\)
In simple words: Fencing goes around the boundary, so first calculate the perimeter, then multiply it by the cost per meter.

Exam Tip: Remember that fencing, boundary, and perimeter all refer to the outer edge distance, unlike area which covers the inside surface.