WEBVTT
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Let’s take a look at graphing points on a coordinate plane.
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The first thing we’ll need are two intersecting lines, but not just any intersecting lines, we need perpendicular lines.
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These lines intersect at a ninety-degree angle, so they’re perpendicular and they’re the start of our coordinate plane.
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Before we say anything else about our coordinate plane, we need to know a few new words.
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The point where these two lines intersect, the point where they cross, is called the origin.
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The line that runs left and right is called the 𝑥-axis.
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The line that runs up and down is called the 𝑦-axis.
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If you look closely on this coordinate plane, you’ll also see some numbers.
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The 𝑥- and 𝑦-axis are kind of like number lines.
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If we’re looking at the 𝑥-axis and counting one, two, three, what number should be at the origin?
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Well the origin should be zero.
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And if we’re looking at the 𝑦-axis as a number line, what should be at the origin?
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Also zero.
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So when we write the origin, we write it like this: zero, zero.
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The reason we write like this is because the coordinates are zero for the 𝑥-axis and zero for the 𝑦-axis.
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The name of this video though is graphing points on a coordinate plane, so let’s get started with graphing.
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But the point of this video is graphing things on a coordinate plane, so let’s get started with that.
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The most important thing to remember is that when we’re graphing things on a coordinate plane, we start with the 𝑥-axis and then we move to the 𝑦-axis.
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The format looks like this: we start with the 𝑥-coordinate, and then we have the 𝑦-coordinate; and these are given in numbers, so we have an open parentheses, the 𝑥-coordinate comma the 𝑦-coordinate, close parentheses.
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In other words, the first number, our 𝑥-coordinate tells us how far left or right and our second coordinate, our 𝑦-coordinate tells us how far to go up or down.
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Again, in order to graph things on a coordinate plane, we need two numbers: an 𝑥-value and a 𝑦-value.
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And 𝑥 always comes first, just like in the alphabet.
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You might be given the coordinate one, three.
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What would it look like to graph one, three?
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Well because we have our 𝑥 and then our 𝑦, we need to go to the right one and up three; and our point is located there.
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So now I want you to try.
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Use the coordinate plane to find the coordinates of the origin and point C.
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By looking at the coordinate plane, you should be able to find the location of the origin and point C.
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First off, for the origin, the origin is always located at zero, zero; and it is located at zero, zero on this graph.
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Point C is located at two, one.
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It’s two to the right and one unit up.
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Sometimes we use coordinate planes to help us read maps.
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Look closely at the map and see if you can find the coordinates of the Ferris wheel, the ice cream truck, and the train.
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Remember, the format is the 𝑥-coordinate, how far left and right, and then the 𝑦-coordinate, how far up and down.
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The Ferris wheel is located six units to the right and six units up.
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The ice cream truck is one unit to the right and two units up.
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And finally, the train is located six units right and two units up.
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I know what you’re thinking.
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Okay, so coordinate planes are good for maps, but who else really uses them?
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Here’s an example, one person that might use coordinate planes is a city planner or an architect.
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They design streets, and they tell us where are the best places to put houses, and they use coordinate plane systems to do that.
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Pilots use coordinate planes in their navigational systems.
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They use coordinate planes to get us from point A to point B, from one city to the next.
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Another really cool job that might use a coordinate plane is marine biologist.
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A marine biologist might use a coordinate plane to map out a shipwreck.
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They have to be really accurate when they describe where they found certain artifacts.
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Now that we’ve talked about how to use a coordinate plane and who might use a coordinate plane, I want to remind you of the vocabulary words we talked about today.
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Coordinate planes consist of an 𝑥-axis and a 𝑦-axis.
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These two lines intersect at the origin, and we always write coordinates with the 𝑥 first and the 𝑦 second.
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If you remember these words and don’t forget to put the 𝑥 first and the 𝑦 second, you’ll be on your way to graphing points in a coordinate plane.