Page 261 - Start Up Mathematics_7

5. Find the missing values:

Base Height Area of Triangle

15 cm _________ 87 cm 2

_________ 31.4 mm 1256 mm 2
22 cm _________ 170.5 cm 2

A

6. ∆ABC is isosceles with AB = AC = 7.5 cm and BC = 9 cm E
(See figure, given alongside). The height AD from A to BC, is 6 7.5 cm
cm. Find the area of ∆ABC. What will be the height from C to 7.5 cm
Ab i.e., CE? 6 cm
B D 9 cm C

7. A gardener wants to fence a circular garden of diameter 21 m.
Find the length of the rope he needs to purchase, if he makes
2 rounds of fence. Also find the cost of the rope, if it costs ` 4
per meter. (Take π = 22 )
7

8. From a circular card sheet of radius 14 cm, two circles of radius
3.5 cm and a rectangle of length 3 cm and breadth 1 cm are
removed. (as shown in the adjoining figure). Find the area of the

remaining sheet. (Take π = 22 )
7
9. A picture is painted on a cardboard 8 cm long and 5 cm wide such that there is a margin of
1.5 cm along each of its sides. Find the total area of the margin.

Exemplar Problems

1. Area of the shaded portion in the given figure is: 5 cm
1 cm
2
(a) 25 cm (b) 15 cm 2
3 cm
2
(c) 14 cm (d) 10 cm 2
3 cm
1 cm
5 cm
2. In the given figure, if PR = 12 cm, QR = 6 cm and P
PL = 8 cm, then QM is:

(a) 6 cm (b) 9 cm 12 cm
(c) 4 cm (d) 2 cm 8 cm
M
3. To find area, any side of a parallelogram can be chosen

as __________ of the parallelogram. L Q 6 cm R

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