Updated By SaraNextGen

On March 11, 2024, 11:35 AM

Question 1:

A square and a rectangular field with measurements as given in the figure have the same perimeter. Which field has a larger area?

Answer:

Perimeter of square = 4 (Side of the square) = 4 (60 m) = 240 m

Perimeter of rectangle = 2 (Length + Breadth)

= 2 (80 m + Breadth)

= 160 m + 2 × Breadth

It is given that the perimeter of the square and the rectangle are the same.

160 m + 2 × Breadth = 240 m

Breadth of the rectangle =   = 40 m

Area of square = (Side)² = (60 m)² = 3600 m²

Area of rectangle = Length × Breadth = (80 × 40) m² = 3200 m²

Thus, the area of the square field is larger than the area of the rectangular field.

Question 2:

Mrs. Kaushik has a square plot with the measurement as shown in the following figure. She wants to construct a house in the middle of the plot. A garden is developed around the house. Find the total cost of developing a garden around the house at the rate of Rs 55 per m².

Answer:

Area of the square plot = (25 m)² = 625 m²

Area of the house = (15 m) × (20 m) =300 m²

Area of the remaining portion = Area of square plot − Area of the house

= 625 m² − 300 m² = 325 m²

The cost of developing the garden around the house is Rs 55 per m².

Total cost of developing the garden of area 325 m² = Rs (55 × 325)

= Rs 17,875

Question 3:

The shape of a garden is rectangular in the middle and semi circular at the ends as shown in the diagram. Find the area and the perimeter of the garden [Length of rectangle is 20 − (3.5 + 3.5) metres]

Answer:

Length of the rectangle = [20 − (3.5 + 3.5)] metres = 13 m

Circumference of 1 semi-circular part = πr 

Circumference of both semi-circular parts = (2 × 11) m = 22 m

Perimeter of the garden = AB + Length of both semi-circular regions BC and

DA + CD

= 13 m + 22 m + 13 m = 48 m­

Area of the garden = Area of rectangle + 2 × Area of two semi-circular regions

Question 4:

A flooring tile has the shape of a parallelogram whose base is 24 cm and the corresponding height is 10 cm. How many such tiles are required to cover a floor of area 1080 m²? (If required you can split the tiles in whatever way you want to fill up the corners).

Answer:

Area of parallelogram = Base × Height

Hence, area of one tile = 24 cm × 10 cm = 240 cm²

Required number of tiles = 

= 45000 tiles

Thus, 45000 tiles are required to cover a floor of area 1080 m².

Question 5:

An ant is moving around a few food pieces of different shapes scattered on the floor. For which food − piece would the ant have to take a longer round? Remember, circumference of a circle can be obtained by using the expression c = 2πr, where r is the radius of the circle.

Answer:

(a)Radius (r) of semi-circular part = 

Perimeter of the given figure = 2.8 cm + πr

(b)Radius (r) of semi-circular part = 

Perimeter of the given figure = 1.5 cm + 2.8 cm + 1.5 cm +π (1.4 cm)

(c)Radius (r) of semi-circular part = 

Perimeter of the figure(c) = 2 cm + πr + 2 cm

Thus, the ant will have to take a longer round for the food-piece (b), because the perimeter of the figure given in alternative (b) is the greatest among all.