Такая задача
A cylindrical tin of height h cm and radius r cm, has surface area, including
its top and bottom, Acm2 .
Write down an expression for A in terms of r, h and π .
A tin of height 6 cm has surface area 54 π cm 2 . What is the radius of the tin?
Another tin has the same diameter as height. Its surface area is 150 π cm 2 .
What is its radius?
A=Sбок+2Sкр=2[tex]\pi rh+ 2 \pi r^{2}[/tex]
A=2[tex]\pi[/tex]r(r+h)
а дальше ерунда какая-то начинается
r=A/(2[tex]\pi[/tex]r) -h
как решать?