## Thursday, February 17, 2011

### Demvry's Textbook Homework

Pages 258-261
Questions 18 and 19

Question:
18.Suki has 30 small linking cubes.
a)She wants to use 18 of them to make a large cube. Is this possible? Why or why not?
b)What number of linking cubes would she use to construct the largest cube she can possibly make?

a)I say this is not possible because I think there is no whole number that could be cubed to be able to equal 18.
b)She would probably need to use 27 cubes to make the largest cube possible (3x3x3).

Question:
19.Melissa has three glass vases. She wants to use one as a decorative fish tank for Harvey the guppy. Which will give Harvey the most water to swim in.

The volume of the one shaped as a cube is 343cm2.
The volume of the one shaped as a rectangular prism is 360cm2.
The volume of the one shaped as a triangular prism is 367.5cm3.

According to the volumes, the triangular prism would've the most water for Harvey the guppy to swim in.

Here are some videos!
Volume of a cube!

Volume of a rectangular prism!

Volume of a triangular prism!

http://www.math.com/tables/geometry/volumes.htm

Inform me if I made a mistake or tell me what I could improve on. Thanks.
Ps - If the letters are over or undersized, ignore it and I'll try to find a way to fix it. If I can't, I'm sorry.