Question

the radius of a right circular cylinder increases by 20% and height remains unchanged find the increase in the curved surface area of cylinder
urgent​

Answer 1

Answer:

Step-by-step explanation:

let,

initial radius of cylinder be 'r'

and height be 'h'

then initial curved surface area= 2πrh

if the radius is increased by 20% then

new radius 'R'= r+20/100r= 20+1/5r                           eq.............1

then the new curved surface area= 2πRh

                                                        = 2π(r+1/5r)h          from eq 1

                                                        = 2πrh+2/5πrh

⇒increase in curved surface area= $\frac{final-initial}{intial}$*100%

                                                       = $\frac{2\pi rh+2/5\pi rh-2\pi rh}{2\pi rh}$*100%

                                                       =$\frac{2/5\pi rh}{2\pi rh}$*100%

                                                       =20%