Question

Geometry question

Answer 1

\(\text{A right angled triangle with hypotenuse 10 inches} \\
\text{and other two sides of variable length is rotated about}\\
\text{ its longest side thus giving rise to a solid. }
\\\text{Find the maximim possible area of such a solid .}\).

Answer 2

by area do you mean total surface area ?

Answer 3

yes i hope it is, the question doesn't specifically mentioned it, i pasted the question as it it given in book

Answer 4

is the answer 75pi ?

Answer 5

Options are
\(a.)\dfrac{250}{3}\pi\quad in^2\\
b.)\dfrac{160}{3}\pi\quad in^2\\
c.)\dfrac{352}{3}\pi\quad in^2\\
d.)\text{none of these}\)

Answer 6

ans given in book is \(250/3\pi\quad in^2\)

Answer 7

Ohk, by longest side they mean "hypotenuse" is it

Answer 8

yes hypotesue is the longest side

Answer 9

i think book is wrong

Answer 10

here i found a solution

http://testfunda.com/Answers/ViewQuestion.aspx?QID=c27d1397-5f3b-41c1-8226-d89852b2e708

Answer 11

http://www.meritnation.com/ask-answer/question/is-made-to-revolve-about-its-hypotenuse-find-the-volum/math/4347896

Answer 12

http://www.meritnation.com/ask-answer/question/is-made-to-revolve-about-its-hypotenuse-find-the-volum/math/4347896

Answer 13

that was a similar question

Answer 14

SA = πr2 + πrl

now in your case the length l is fixed so the area depends on r

so do get the max value you find the derivative dA/dr

= 2pi r + pi l

for max value this = 0

pi (2r +l) = 0

r= l/2

A= pi (25 + 50) = 75 pi

Answer 15

The other examples refer to the max volume.

It does appear that the correct answer is NOT given in your otions

Answer 16

The other examples refer to the max volume.

It does appear that the correct answer is NOT given in your options

so 'none of these'

NOTE - since the other discussions were inconclusive I have taken the liberty of posting the answer - I normally will NOT do this,

Answer 17

u cant count the dotted surface here u have to only count the lateral surface area

Answer 18

OK - I see where I went wrong - I rotated about a shorter side ot give a single cone.

I'll try again