Question

plz answer.. !!!!!!!

Answer 1

suppose we take the diameter as 28 cm
radius = 14 cm
surface area = 4*π*r^2
= 4*22/7*14*14
= 2464 cm^2

Now,
New diameter = 28 -28*75/100
= 21 cm.

So,
radius = 21/2 = 10.5 cm.
Now,
New surface area = 4*22/7*10.5*10.5
= 1386 cm^2.

now,
Decrease in surface area= 2464 - 1386 = 1078.
So,
DECREASE IN THE SURFACE AREA = 1078/2464 * 100
= 43.75% of decrease in the surface area.