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help.. with math problem, kind of hard?
I need help with the following problem (#18)
I am having trouble because its a 3-d shape as opposed to a regular one.
Need help solving it. I know i do them separately then add, but im not sure? |:
http://i39.tinypic.com/14ij4oj.jpg
thanks for your time
1 Answer
- jcherry_99Lv 78 years agoFavorite Answer
These are both the same, just different numbers. I'll do a and leave b for you.
Volume
======
radius = d/2 = 6 cm / 2 = 3 cm
height = 8 cm
volume of cylinder = pi r^2 * h = pi * (3cm)^2 * 8cm = 72* pi
Volume of hemisphere = 2/3 pi r^3 = 2/3 * pi (3cm)^3 = 18 pi
Total Volume = 90 pi You can take pi to be whatever value suits you
Surface area
=========
Cylinder
- - - - - -
You have to be a bit careful here. The surface area of the cylinder is 1 bottom and 1 circular wall.
Area = pi * r^2 + 2pi*r*h
Area = pi * 3^2 + 2pi * 3 * 8
Area = 9pi + 48pi
Area = 57 cm^2 * pi
Hemisphere
Area = 2 pi r^2
Area = 2 pi * 3^2
Area = 18 pi
Total Surface area = 57 pi + 18 pi = 75 pi