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[MUSIC]

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This practice session covers
basic JavaScript functions.

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It's a great followup to the fifth
part of the JavaScript Basics course.

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If you haven't taken that yet, and
find this practice session too difficult,

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then go through the first five
parts of that course first.

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I've added a link in
the teacher's notes below.

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For this practice session,
you'll write four functions.

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Call those functions and
output the results to the console.

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It's pretty simple but
combines the basics of creating and

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using JavaScript functions.

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I've attached a workspace to this video
which includes some starter files and

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instructions.

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Open up the workspace and
open up the geometry.js file.

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You'll see six instructions
listed as JavaScript comments.

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Here's what you should do.

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First attach the JavaScript
file to the index.html file.

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After all, the program won't work at
all unless the web page loads it.

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Next create a function that
calculates the area of a rectangle.

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To calculate the area of a rectangle,
you multiply the width by the height.

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So this function needs
to accept two arguments,

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do some math,
then return the results back.

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Then you'll create another
function to calculate the volume

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of a rectangular prism.

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Also known as a box.

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For that, you multiply the width
by the height by the length.

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This function should return the volume.

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Now the next two functions involve
calculating the area of a circle and

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the volume of a sphere.

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These both require using the JavaScript
math object to get the value of pi.

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And to use a method that lets you
raise the number to a certain power.

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For example x to the second power or
x squared.

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Now I didn't cover those in
JavaScript basics course, so

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you'll need to do a bit of research
to figure out how to use them.

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I've included links in
the teacher's notes below.

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Okay so if you have the radius of a circle
to calculate the area of a circle,

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you take pi times the radius squared.

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Squared is also refered as the second
power or to the second power.

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So the function will receive
a radius value and return the area.

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The last function will calculate
the volume of a sphere.

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To do that you multiply four thirds by pi,
by the radius cubed or

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the radius to the third power.

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Okay now finally you'll
add four lines to log out

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the results of your function
to the JavaScript console.

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It's not super exciting to look at, but
this is what your output should look like,

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something like this.

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Now if you wanna do some quick study
before tackling this practice session.

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In the teacher's notes look for

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links to videos that can help
you solve this challenge.

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But if you're ready, go for it.

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Program your solution and I'll show
you my solution in the next video.