Question

Please please please help me with these. Please show work. Thank you if you answer

Answer 1

4
If the cylinder is open it means there is no area of the top
So the surface of cylinder would be lateral surface and base area


`A=2\pi rh+\pi r^2\\\\A=2\pi\cdot4\cdot7+\pi\cdot4^2=56\pi+16\pi=72\pi\approx72\cdot3,14=226,08`

5
If the cylinder is close it has two areas of base


`A=2\pi rh+2\pi r^2\\\\A=2\pi\cdot10\cdot9+2\pi\cdot10^2=180\pi+200\pi=360\pi\approx360\cdot3,14=1130,4`

Answer 2

4. A=2πrh+2πr2=2·π·4·7+2·π·42≈276.46015 = 276
5. A=2πrh+2πr2=2·π·10·9+2·π·102≈1193.80521 = 1193.81