Question

all my brainly friends who are senior to me please help me how to solve complicated problems in surface areas and volumes please you put some new questions based on these and also post the answers so that I can easily understand what is the trick to solve ​

Answer 1

Answer:

alright

surface area is nothing but the area exposed by the body. if the area is in the shape of a rectangle then it is l×b

triangle is 1/2×l×b.

now the tough ones are surface area of a cone, cylinder or any other things like that.

for cylinder the area of the top flat surface is πr^2

now for the curved surface think about it in this way. imagine you are unfolding a cylinder and spread it on a paper. it should form a rectangle. area of rectangle is l×b

if u fold the paper back into a cylinder u will observe

that the breadth becomes the circumference of the top circular end while the length becomes the height.

so breadth will be 2πr and length will be height.

so the area of curved surface is 2πr×h.

so total surface area is two circular surface and curved surface. so 2πr^2+ 2πrh.

similarly for cone total surface area is πr^2+ πrl. where l is the length along the side of cone. l is also equal to

$\sqrt{ {h}^{2} + {r}^{2} }$

where h is height and r is radius