#### Measurements Book Back Questions

8th Standard EM

Reg.No. :
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Maths

Time : 00:45:00 Hrs
Total Marks : 30
5 x 1 = 5
1. The ratio between the circumference and diameter of any circle is_______

()

π

2. The radius of a circle of diameter 24 cm is __________.

()

12 cm

3. The three dimensions of a cuboid are _______.

()

4. The meeting point of more than two edges is called as ______.

()

Vertex

5. The cross section of a solid cylinder is _______.

()

Circle

6. 5 x 1 = 5
7. Area of a circle

8. (1)

πr2

9. Circumference of a circle

10. (2)

Cylinder

11. Area of a quadrant of a circle

12. (3)

Triangular Prism

13. (4)

$2{ \pi r }^{ }$

14. (5)

$\frac { 1 }{ 4 } { \pi r }^{ 2 }$

3 x 2 = 6
15. For the sectors with given measures, find the length of the arc, area and perimeter.(π=3.14)
(i) central angle 45º , r = 16 cm
(ii) central angle 120º, d =12.6 cm
(iii) central angle 60º, r =36 cm
(iv) central angle 72º, d =10 cm

16. Find the central angle of each of the sectors whose measures are given below. $\left( \pi =\frac { 22 }{ 7 } \right)$

 S.No area (A) length of the arc (l) radius (r) (i) 462 cm2 - 21 cm (ii) 18.48 cm2 - 8.4 cm (iii) 44 m 35 m (iv) - 22 mm 105 mm
17. Find the area of a sector whose length of the arc is 50 mm and radius is 14 mm.

18. 3 x 3 = 9
19. The radius of a sector is 21cm and its central angle is 120 °. Find perimeter of sector.

20. A circular shaped gymnasium ring of radius 35cm is divided into 5 equal arcs shaded with different colours. Find the length of each of the arcs.

21. Four identical medals, each of diameter 7cm are placed as shown in Fig. 2.20. Find the area of the shaded region between the coins.

22. 1 x 5 = 5
23. Find the area of the blue shaded and the grey shaded part of the given Fig.2.28.(π = 3.14)