Answers

  • qais
  • Content Quality
2016-02-08T11:19:08+05:30

This Is a Certified Answer

×
Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Let the outer radius be R 
and inner radius be r
total surface area = inner surface area + outer surface area +2(area of                                            thickness)
                             = 2πrh + 2πRh + 2π(R² -r²)
⇒338π = 20πr + 160π + 128π - 2πr²
⇒2πr² - 20πr + 50π =0
⇒r² -10r + 25 =0
⇒(r -5)²=0
⇒r =5 cm
so thickness of the metal in cylinder = R- r = 8- 5 = 3 cm

0