Page 199 - Start Up Mathematics_6

Inference: The perimeter of a regular polygon is the measure of one side multiplied by the
number of sides.

EXERCISE 10.1
1. Find the perimeters of the following:

(a) A rectangle of length 16 cm and breadth 10 cm
(b) A parallelogram of length 21 cm and breadth 15 cm

(c) A triangle with sides measuring 10 cm, 14 cm and 16 cm
2. How much does Shamim have to walk to go around a square field of side 10 m?

3. What is the length of a coloured tape required to stick on the sides of a rectangular scenery.
The length of the scenery is 20 cm and breadth is 12 cm.
4. How much wire is required to fence a rectangular field 1 km long and 500 m broad?

5. What will happen to the perimeter of a rectangle if its length is doubled and breadth remains
the same?
6. Two sides of a triangle are 10 cm and 12 cm. The perimeter of the triangle is 35 cm. What
will be the length of the third side?

7. Find the perimeter of a rectangular lawn whose length is 20 m 50 cm and breadth is 12 m
20 cm.
8. A rectangular piece of plot measures 0.6 km by 0.5 km. Each side is to be fenced with
5 rows of wires. What is the length of the wire needed? If the wire costs ` 9 per metre,
what will be the cost of the wire required for fencing?

9. Ranjan walks around a rectangular park of length 60 m and breadth 40 m and Smita walks
around a square park of side 55 m. Both take 3 rounds each. Who walks more distance and
by how much?
10. A rectangular piece of land is to be fenced for an exhibition. The length of the exhibition land
is 250 m and its breadth is 200 m. We need to keep an entrance of 10 m and an emergency
exit of 5 m. If the cost of this special fencing is ` 175 per metre, what will be the total cost
of fencing?
11. A rectangular field is 15 m long and 10 m wide. Another rectangular field having the same
perimeter has its sides in the ratio 4 : 1. Find the dimension of the rectangular field.

Area

We know that a closed figure encloses some region in it. Area is the surface or region enclosed
in a closed plane figure. Following are some pairs of figures. Can you identify the figure in the
pairs occupying greater areas:

(a) (b) (c) (d)

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