Q The surface area of cuboid is 1792 square cm if its l,b,h are in the ratio 4:2:1 Find - Maths - Surface Areas and Volumes

Question

Q The surface area of cuboid is 1792 square cm if its l,b,h are in
the ratio 4:2:1 Find the length of the cuboid
Q A cylinder and cone have equal radius of 21 cm and height of
cylinder is 8 cm whereas the height of the cone is 16 cm Find the
ratio of volume of cylinder & cone
Q An area of a circular base of a cylinder is 154 square cm Find
the TSA , CSA and vol of cylinder if h=7 cm
Q Find the ratio of TSA of the hemisphere to the TSA of sphere,
they both have the same radius
Q The floor of a rectangular hall has perimeter 220 m the cost of
painting the 4 walls at the rate of 210 per square meter is Rs 2400
Find the h of the hall

Abhishek Jha · Accepted Answer

Dear Student,
Here is the solution of your asked query:
Q 3
 Let r be the radius of circular base of cylinder
So, area of circular base of cylinder=πr2=154cm2⇒227×r2=154⇒r2=154×722=49⇒r=±49=±7Since radius can't be negative so neglecting r=-7So, radius of circular base of cylinder = 7cmAnd height=7cmThen, TSA =2πrr+h=2×227×7×7+7=616cm2And CSA=2πrh=2×227×7×7=308cm2And volume of cylinder=πr2h=227×72×7=1078cm3
Regards