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Write four JavaScript functions to calculate areas and volumes.
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Mozilla Developer Network Reference
[MUSIC]
0:00
This practice session covers
basic JavaScript functions.
0:04
It's a great followup to the fifth
part of the JavaScript Basics course.
0:07
If you haven't taken that yet, and
find this practice session too difficult,
0:11
then go through the first five
parts of that course first.
0:15
I've added a link in
the teacher's notes below.
0:18
For this practice session,
you'll write four functions.
0:20
Call those functions and
output the results to the console.
0:23
It's pretty simple but
combines the basics of creating and
0:27
using JavaScript functions.
0:30
I've attached a workspace to this video
which includes some starter files and
0:31
instructions.
0:35
Open up the workspace and
open up the geometry.js file.
0:36
You'll see six instructions
listed as JavaScript comments.
0:39
Here's what you should do.
0:43
First attach the JavaScript
file to the index.html file.
0:45
After all, the program won't work at
all unless the web page loads it.
0:48
Next create a function that
calculates the area of a rectangle.
0:52
To calculate the area of a rectangle,
you multiply the width by the height.
0:56
So this function needs
to accept two arguments,
1:01
do some math,
then return the results back.
1:04
Then you'll create another
function to calculate the volume
1:06
of a rectangular prism.
1:09
Also known as a box.
1:11
For that, you multiply the width
by the height by the length.
1:13
This function should return the volume.
1:16
Now the next two functions involve
calculating the area of a circle and
1:19
the volume of a sphere.
1:23
These both require using the JavaScript
math object to get the value of pi.
1:24
And to use a method that lets you
raise the number to a certain power.
1:29
For example x to the second power or
x squared.
1:33
Now I didn't cover those in
JavaScript basics course, so
1:37
you'll need to do a bit of research
to figure out how to use them.
1:40
I've included links in
the teacher's notes below.
1:43
Okay so if you have the radius of a circle
to calculate the area of a circle,
1:46
you take pi times the radius squared.
1:51
Squared is also refered as the second
power or to the second power.
1:54
So the function will receive
a radius value and return the area.
1:58
The last function will calculate
the volume of a sphere.
2:02
To do that you multiply four thirds by pi,
by the radius cubed or
2:05
the radius to the third power.
2:09
Okay now finally you'll
add four lines to log out
2:11
the results of your function
to the JavaScript console.
2:15
It's not super exciting to look at, but
this is what your output should look like,
2:19
something like this.
2:23
Now if you wanna do some quick study
before tackling this practice session.
2:24
In the teacher's notes look for
2:27
links to videos that can help
you solve this challenge.
2:29
But if you're ready, go for it.
2:31
Program your solution and I'll show
you my solution in the next video.
2:33
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