Curved surface area of the cylinder = 2?rh
= 2 x (22/7) x 7 x 160
= 7040 sq cm
Let the height and radius and radius of solid cylinder be h and r cm respectively
Given that, radius (r) = 5 cm
and total surface area = 660 cm2
? 2?rh + 2?r2 = 660
? 2?r(h + r) = 660
? (h + 5) = 330/5? = 330/5 x 7/22
? h = 66 x (7/22) - 5 = 21 - 5
? Required height = 16 cm
Given, r1 = 1 cm, h1 = 30 cm, h2 = 300 cm.
Volume of rod = Volume of wire
? ?r12h1 = ?r22h2
? ? x (1)2 x 30 = ? x r22 x 300
? r22 = 30/300
? r2 = 1/?10 cm
? diameter = 2r2
= 2 x 1/?10 = 2/?10cm.
Given, lateral surface area = 94.2 sq cm
? 2?rh = 94.2
? r = 94.2/(2?h) = 94.2/(2 x 3.14 x 5) = 3 cm
Total surface area of cylinder = 2?r(h + r)
Given that, r = 14/2 = 7 cm, h = 40 cm
? Required total surface area = 2 x (22/7) x 7 x (40 + 7)
= 44 x 47 = 2068 sq cm
Given, r = 7 cm, h = 80 cm
Volume = ?r2h = (22/7) x 7 x 7 x 80
= 12320 cm3
Let radii be 2r and 3r and heights be 5h and 3h.
? Ratio of volumes = [?(2r)2 x 5h] / [?(3r)2 x 3h]
= 20/27 = 20 : 27
Given that , 2?rh = 264
and ?r2h = 924
? ( ?r2h) / (2?rh) = 924 / 264 = 7/2
? r/2 = 7/2
? r = 7
? d = 2r = 14 m
Also, 2 x (22/7) x 7 x h = 264
? h = 264 / 44 = 6
? d/h = 14/6 = 7/3 = 7 : 3
According to the formula,
Percentage change in volume is directly proportional to the height,
So percentage decrease in volume = 8%
According to the formula
Percentage increase in volume
= (2k + k2/100)% = ( 2 x 25 + 252/100)%
= (50 + 625/100)% = (50 + 6.25)%
= 56.25%
Here, A = -8%, B = 4%
According to the formula,
Net effect on volume = [2A + B + A2 + 2AB/100 + A2B/1002]%
= [2 x (-8) + 4 + (-8)2 + 2 x (-8) x 4 /100 + (-8)2 x 4 /1002]
= [-16 + 4 + 64 - 64/100 + 256/104]%
=[-12 + 0 + 0.0256]%
= -11.9744% (decrease)
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