The total surface area of a solid right circular cylinder is 231 cm2, itscurved surface is 2rd3 of the total surface area. Find the radius of thebase and height.
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The surface area of cylinder is 2πr(r+h) = 231cm2.....(1)
so, its curved surface area is=2/3(231)cm2
2πrh=154 cm2......(2)
putting value of 2πrh from equation (1) in equation (2) we will get
=> 2πr2+154=231
=>2πr2=231-154
=>2πr2=77
=>r2=77/(2π)
=> r2=12.25 (π=22/7)
=> r=(12.25)^(1/2) cm
=> 3.5 cm
If we put the value of r=3.5cm in equation (2) we will get
=> 2πrh=154
=> 2(22/7)*3.5* h=154
=> 22h=154
=> h=154/22 cm
=> 7cm(ans)
so, its curved surface area is=2/3(231)cm2
2πrh=154 cm2......(2)
putting value of 2πrh from equation (1) in equation (2) we will get
=> 2πr2+154=231
=>2πr2=231-154
=>2πr2=77
=>r2=77/(2π)
=> r2=12.25 (π=22/7)
=> r=(12.25)^(1/2) cm
=> 3.5 cm
If we put the value of r=3.5cm in equation (2) we will get
=> 2πrh=154
=> 2(22/7)*3.5* h=154
=> 22h=154
=> h=154/22 cm
=> 7cm(ans)
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