Question

total surface area of a cylinder is 420cm2 and its base circumference is 60cm find the sum of its height and radius​

Answer 1

Given:-

• Total Surface Area of the cylinder = 420 cm²
• Base circumference = 60 cm

To find:-

• The sum of its height and radius (r + h)

Solution:-

Let the radius of the cylinder be r and height be h.

We know,

✭ Total Surface Area of cylinder = 2πr(r + h) sq.units ........... (i)

Also We know,

Circumference of the circle = 2πr ............ (i)

Now,

We are given with the Circumference of the Circle and the total Surface area of the cylinder

Hence,

2πr = 60 cm

Putting the value of 2πr in equation (i)

Total Surface Area = 60(r + h)

⇒420 = 60(r + h)

⇒ 420/60 = r + h

⇒ r + h = 7

∴ The sum of radius and height of the cylinder is 7 cm.

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Other formulas related to cylinder:-

• Volume of cylinder = πr²h cu.units
• Lateral Surface Area of cylinder = 2πrh sq.units.

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