Question

a rectangular strip of size 25 cm × 7 cm is rotated about the longer side find the volume and the whole surface area of the solid Thus generated

Answer 1

Height is 25 cm and radius is 7 cm
Volume= 22/7*25*7*7
=3850m3
Total surface area =2*22/7*r(h+r)
=2*22/7*7(25+7)
=44*32
=1408m2

Hope it helps!!!

Answer 2

Answer:

$V=3846.5 cm^3$  

$S=1406.72 cm^2$

Step-by-step explanation:

Given : A rectangular strip of size 25 cm × 7 cm is rotated about the longer side.

To find : The volume and the whole surface area of the solid?

Solution :

Rectangular strip has radius, r = 7 cm

Height, h = 25 cm

Volume of the solid, $V=\pi r^2 h$

$V=(3.14) (7)^2 (25)$        

$V=(3.14)(49)(25)$  

$V=3846.5 cm^3$  

Total surface of the solid is $S=2\pi r(r+h)$

$S=2(3.14)(7)(7+25)$

$S=2(3.14)(7)(32)$

$S=1406.72 cm^2$