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#### Measurements Important Questions

8th Standard EM

Reg.No. :
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Maths

Time : 01:00:00 Hrs
Total Marks : 50
5 x 1 = 5
1. The ratio between the circumference and diameter of any circle is_______

()

π

2. The longest chord of a circle is __________.

()

diameter

3. A part of circumference of a circle is called as ________.

()

an arc

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

()

Vertex

5. If a net of a 3-D shape has six plane squares, then it is called ______.

()

Cube

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

8. (1)

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

9. Area of the sector of a circle

10. (2)

πr2

11. Area of a quadrant of a circle

12. (3)

Square Pyramid

13. (4)

Cylinder

14. (5)

$=\frac { { \theta }^{ 0 } }{ { 360 }^{ 0 } } \times { \pi r }^{ 2 }$

9 x 2 = 18
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. Find the area of a sector whose perimeter is 64 cm and length of the arc is 44 cm.

19. Find the perimeter and area of the combined figures given below. $\left( \pi =\frac { 22 }{ 7 } \right)$

20. Find the area of the combined figure given, formed by joining a semicircle
of diameter 6 cm with a triangle of base 6 cm and height 9 cm. ( π = 3.14 )

21. Which 3-D shapes do the following nets represent? Draw them.

22. Draw the net for the cube of side 4 cm in a graph sheet.

23. In a rectangular field which measures 15 m × 8m, cows are tied with a rope of length 3m at four corners of the field and also at the centre. Find the area of the field where none of the cow can graze. (π = 3.14)

24. 4 x 3 = 12
25. The radius of a sector is 21cm and its central angle is 120 °. Find the length of the arc

26. The radius of a sector is 21cm and its central angle is 120 °. Find perimeter of sector.

27. Find the central angle and area of a palm leaf fan (sector) of radius 10.5 cm and whose perimeter is 43 cm $\left( \pi =\frac { 22 }{ 7 } \right)$

28. From the three vertices of an equilateral triangle of side 12 cm, Nishanth cuts sectors of 5 cm radius each and forms the following shape. Find the area of that shape. (π=3.14)

29. 2 x 5 = 10
30. Find the perimeter and area of the given Fig.2.27. $\left( \pi =\frac { 22 }{ 7 } \right)$

31. A key-chain is in the form of an equilateral triangle and a semicircle attached to a square of side 5 cm as shown in the Fig.2.30. Find its area.(π=3.14, √3=1.732)