Question

Okay so I have multiple questions that I need help with so I will put them below and you will get more points! Once you know the answer put in the comments Answer one is so I no what it is answer two is etc.
Question number one:
Find the volume of a cylinder with a diameter of 8 inches and a height that is three times the radius. Use 3.14 for pi and round your answer to the nearest hundredth. (Hint: You may only enter numerals, decimal points, and negative signs in the answer blank)

Question 2:
Given a soda can with a volume of 21 and a diameter of 6, what is the volume of a cone that fits perfectly inside the soda can? (Hint: only enter numerals in the answer blank)

Question 3:
Given a cube with a volume of 27 cm3, what is the volume of a square pyramid that can fit perfectly inside the cube?
A)3cm3
B)6cm3
C)9cm3
D)12cm3
If you can answer all of these you will be getting 20 points only one of these you get 5 and only two of these 15 points so answer all three to get more points.

Answer 1

Vcylinder=hpir^2
Vcone=(1/3)hpir^2

d/2=r

so



1.
d=8
r=8/2=4
h=3r
h=3(4)
h=12
V=12*3.14*4^2
V=602.88 in^2


2. cone that fits has same base area and therefor same radius
d=6
r=6/2=3
rcone=3
find height of can
V=hpir^2
21=h*3.14*3^2
21=h*3.14*9
0.7431=h
so
cone height=0.7431
radius=3
V=(1/3)(0.7431)(3.14)(3^2)
V=7 cubic units




3.
same base
find dimentions
s=s=s
V=s^3
27=s^2
3=s
Vsquarepyramid=(1/3)hs^2
s=legnth of base
h=height
h=side
V=(1/3)(3)(3^2)
V=9
C






1. 602.88 in^2
2.  7 cubic units
3. 9cm^3, C