1. ## Urgent Measurement Question

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2. well for no. 1 you will need to use the formula for the volume of a sphere
which is
V= 4/3r^3 (someting like that) sub the values in and solve for r

3. Could anyone else provide more detailed answer?

4. Originally Posted by ~NeonFire372~
I have a few questions:

1. How do I calculate the radius of the sphere with a volume of 45.7 metres^3.?
for a sphere, the volume is given by

$\displaystyle V = \frac 43 \pi r^3$

where $\displaystyle r$ is the radius. you are given V, so we have:

$\displaystyle 45.7 = \frac 43 \pi r^3$

just solve for $\displaystyle r$

2. How can I find the height of this? A cone-shaped unit holds 5000 cubic metres (m^3). The radius is 15 metres.
The volume of a cone is given by:

$\displaystyle V = \frac 13 \pi r^2 h$

where $\displaystyle r$ is the radius and $\displaystyle h$ is the height.

you are given V and r, so we have:

$\displaystyle 5000 = \frac 13 \pi (15)^2 h$

just solve for $\displaystyle h$

3. How do I calculate the surface area and volume of the following spheres:

a) The sphere has a radius of 10cm.
b) The sphere has a radius of 5cm.
c) The sphere has a radius of 15.2cm.
d) The sphere has a radius of 20cm.
The surface area for a sphere is given by:

$\displaystyle S = 4 \pi r^2$

where $\displaystyle r$ is the radius. just plug in the value of r for each and solve for S

do the same for the volume. i gave you the formula earlier

5. Originally Posted by Jhevon
for a sphere, the volume is given by

$\displaystyle V = \frac 43 \pi r^3$

where $\displaystyle r$ is the radius. you are given V, so we have:

$\displaystyle 45.7 = \frac 43 \pi r^3$

just solve for $\displaystyle r$

The volume of a cone is given by:

$\displaystyle V = \frac 13 \pi r^2 h$

where $\displaystyle r$ is the radius and $\displaystyle h$ is the height.

you are given V and r, so we have:

$\displaystyle 5000 = \frac 13 \pi (15)^2 h$

just solve for $\displaystyle h$

The surface area for a sphere is given by:

$\displaystyle S = 4 \pi r^2$

where $\displaystyle r$ is the radius. just plug in the value of r for each and solve for S

do the same for the volume. i gave you the formula earlier
I get most of it but can you explain exactly how I 'solve for h' in the height one?