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Geometry and Measurement Videos 88 videos

SAT Math 1.1 Geometry and Measurement
719 Views

SAT Math 1.1 Geometry and Measurement. What is the circumference of the circle?

SAT Math 1.2 Geometry and Measurement
246 Views

SAT Math: Geometry and Measurement Drill 1, Problem 2. If A = (0, 4), B = (-3, 2), and C = (1, 0), which point is in the interior of angle ABC?

SAT Math 2.3 Geometry and Measurement
267 Views

SAT Math 2.3 Geometry and Measurement. Find the length of AB.

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SAT Math 11.2 Geometry and Measurement 178 Views


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SAT Math 11.2 Geometry and Measurement


Transcript

00:02

Here’s your shmoop du jour, brought to you by translated lines.

00:06

Sometimes they're even foggier than Blurred Lines.

00:10

The line y = -2x + 4 is reflected over the y-axis, then translated down one unit and right two units.

00:18

What is its new y-intercept?

00:23

All right, so we’re talking about a line… on a graph…

00:25

The line in question is y = -2x + 4.

00:28

Here’s our graph. Now…where would that line go?

00:32

Well, if y is zero, then x would have to be 2… so let’s draw a point on the x axis at (2,0).

00:39

If we want x to be zero…it would create a point of intersection at the y-axis at (0,4).

00:44

So…la la la… connecting the dots…

00:46

And…there’s our line.

00:48

Now…what does this problem want us to do with it?

00:51

Cast it into a lake and see if we can catch ourselves a trout?

00:54

Uh, no. Wrong kinda line. First it wants us to REFLECT the line across the y-axis.

01:00

Well, one point is right ON the y-axis, so… that guy ain’t goin’ nowhere.

01:04

In fact, the entire line is pretty much just going to pivot around that point, sorta like a hinge.

01:10

What about our other point, the one at (2,0)?

01:13

Yeah, that one gets reflected across, and becomes (-2,0).

01:16

So our new line looks like this: Last step… we need to translate… or shift…

01:21

the line down one unit, and two to the right.

01:24

This time we move both points…like so…

01:27

…and there’s our line’s final resting place.

01:29

So…where’s the new y-intercept?

01:31

Right here… at negative 1. And we have our answer.

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