Page 244 - Start Up Mathematics_7

2
3. The area of a triangle is 84 cm . Find the altitude corresponding to the side measuring
14 cm.
4. The adjacent sides of a parallelogram PQRS are 12 cm and S 8 cm R

6 cm as shown in the given figure. The height corresponding
to side QR is 8 cm. Find the: h
(a) area of the parallelogram P 12 cm Q

(b) altitude corresponding to the base PQ

5. The adjacent sides of a parallelogram are in the ratio 5 : 3. A
If the longer of the two sides is 7.5 cm, find the perimeter
of the parallelogram. 12 cm
E
6. In ∆ ABC, AB = 12 cm, BC = 9 cm and AD = 6 cm 6 cm
(See Fig.) Find the:
(a) area of ∆ ABC B 9 cm C D

(b) altitude CE

7. The area of a triangle is equal to the area of a square whose each side measures 10 m. Find
the length of the side of a triangle corresponding to the altitude measuring 5 m.
2
8. A field in the form of a parallelogram has an area of 432 m .
Find the length of its diagonal on which the perpendiculars
drawn from two vertices on either side of it are 12 m long. S R

9. PQRS is a rectangle with dimensions 28 m by 20 m. POQ O
is a triangle such that O is the point of intersection of the 20 m
diagonals. Find the area of the shaded region.

10. Calculate the missing measurements in the following table: P 28 m Q

S. No. Figure Base Height Area
1. Triangle ............ cm 18 cm 306 cm 2

2. Parallelogram ............ m 4.9 m 25.48 m 2
3. Parallelogram 250 m ............ m 2 hectare

Circumference
The length of the boundary of a circle is its circumference.

Maths Lab Activity
Objective: To find the ratio of the circumference of a circle to its diameter

Step 1: Take some circular objects that we use in our daily life such as bangle, CD, base of
cylinder or a bucket.
Step 2: Measure the diameter of each circular object.

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