Page 260 - Start Up Mathematics_7

Values and Life Skills

1. The altitude of a field in the form of a triangle is half of its base. If the cost of irrigating the
field at the rate of ` 280 per hectare is ` 4,480, find its base and altitude.
What is the importance of irrigation in agriculture?

2. A circular wire in the form of a ring is cut and converted into an equilateral triangle of side
44 dm. Find the radius of the ring.
What is the importance of minimizing the wastage while using the resources?

3. A horse is tethered to one corner of a rectangular field measuring 60 m by 40 m. The rope is
21 m long. How much area can the horse graze?
How should you take care of your pets?
4. A farmer has a square field that is 60 m wide.

(a) Find the cost of fencing the field if it costs ` 12 per metre.
(b) The farmer wants to spray pesticide on the field, which costs ` 7 per square metre. Calculate
the total cost.

What are the harmful effects of using excessive pesticides?
5. A room is 5.8 m long, 4.2 m wide and 3.2 m high. It has one door measuring 1.2 m × 2.5 m

and three windows each measuring 1 m × .75 m. Find the cost of whitewashing its walls at
the rate of ` 30 per square metre.
Why should you not write on the walls?

Some NCERT Textbook Questions

1. The perimeter of a rectangular sheet is 100 cm. If the length is 35 cm, find its breadth. Also
find the area.
2. The area of a square park is the same as of a rectangular park. If the side of the square park
is 60 m and the length of the rectangular park is 90 m, find the breadth of the rectangular
park.

3. A wire is in the shape of a rectangle. Its length is 40 cm and breadth is 22 cm. If the same
wire is rebent in the shape of a square, what will be the measure of each side.
Also find which shape encloses more area?

4. Find the missing values:

S. No. Base Height Area of the Parallelogram

a. 20 cm 246 cm 2

b. 15 cm 154.5 cm 2

c. 8.4 cm 48.72 cm 2

d. 15.6 cm 16.38 cm 2

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