Question

radius of base of a cylinder and it's height are given find the curved surface area and total surface of the area r=1.4cm,h=2.1

Answer 1

Curved surface area of cylinder =
$2\pi rh$
=2 x 22/7 x 1.4 x 2.1
=2 x 22 x 1.4 x 0.3
=44 x 1.4 x 0.3
=19.6 x 0.3
=5.88 cm



Total surface area of cylinder =
$2\pi \: r ( r + h)$
=2 x 22/7 x 1.4 (1.4+2.1)
=2 x 22 x 0.2 (3.5)
=44 x 0.2 x 3.5
= 8.8 x 3.5
=30.8 cm

Answer 2

curved surface area of cylinder= 2pierh
=2×22/7×1.4×2.1
=2×22×0.2×2.1
=18.48sqcm

Total surface area of cylinder= 2 pie r (r+h)
=2×22/7×1.4×1.4+2.1
=2×22×0.2×1.4+2.1
=14.42sqcm.