Question

Section A: 1x6-6
1) Find the area of an equilateral triangle with side 4V5cm.
2) Curved surtace area is 22m2 and r = 0.7m, find height of cylinder.
3) Write the total surface area of cylinder.
4) The perimeter of a triangular field is 144m and ratio of sides are 3:45. Find
its sides
5) A cylindrical vessel is filled with 154cmof water. If radius of tis base is
3.5cm, find the depth of water.
6) Find the area of right angled triangle whose base is 1.5cm. Find the depth
of water.
Section B: 3x4=12
7) A hollow copper cylindrical copper pipe is 200cm long. If its inner and outer
diameter are 8cm and 12cm respectively. Find how many cubic cm of
copper has been used in making the pipe (r = 3.14)
8) Find area of an isosceles triangle which has perimeter 30cm and each of
its equal side is 12cm.
A cylindrical pillar is 50cm in diameter and 3.5m in height. Find cost of
painting its C.S.A. at rate of 12.50 per m2.
10) A triangle and a parallelogram have the same base and same area. If sides
of the triangle are 26cm, 28cm, 30cm and parallelogram stands on base
28cm. Find height of parallelogram.
Section C: 4x3=12
11) If a board is in shape of trapezium with parallel sides as 28cm, 25cm and
non-parallel sides are 25cm, 26cm. Find area of board.
12) A closed cylindrical tank made of steel is 4.2m in diameter and 4.5m high.
Find how much steel was actually used it of the steel actually used was
wasted in making the tank.
13) If the lateral surface of a cylinder is 94.2cm& its height is 5cm, then find
(i) radius of its base (ii) volume.
​

Answer 1

Given :  Side of Equilateral triangle

To find : Area of Triangle

Solution:

Area of an equilateral triangle  = (√3 / 4) ( Side)²

Side of triangle = 4√5  cm

Area of triangle =  (√3 / 4) (4√5)²

=   (√3 / 4) 80

= 20√3  cm²

Curved surface area of cylinder = 2 π r h

r = 0.7 m

h  = ?

π = 22/7

22 = 2 (22/7) * (0.7) * h

=> h = 5 m

the total surface area of cylinder.  = 2 π r ( h + r)

The perimeter of a triangular field is 144m and ratio of sides are 3:45. Find

its sides

3x + 4x + 5x = 144

=> 12x = 144

=> x = 12

Sides are 36 m . 48 m , 60 m

please post question one by one

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