SAT Math 11.2 Geometry and Measurement

SAT Math 11.2 Geometry and Measurement

GeometryCoordinate Geometry
Transformations
Understand similarity in terms of similarity transformations
Geometry and MeasurementTransformations
Mathematics and Statistics AssessmentTransformations and Symmetry
Parallel and Perpendicular LinesEquations and Slopes of Lines
Product TypeSAT Math
SAT MathGeometry and Measurement
Similarity, Right Triangles, and TrigonometryUnderstand similarity in terms of transformations

Transcript

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.