# SAT Math 4.2 Geometry and Measurement

SAT Math 4.2 Geometry and Measurement

 Additional Topics in Math Right triangle problems (word problems) Congruence Experiment with transformations in the planeUnderstand congruence in terms of rigid motion Geometry Experiment with transformations in the planeTrianglesUnderstand congruence in terms of rigid motionsUnderstand similarity in terms of similarity transformations Geometry and Measurement Transformations Language English Language Product Type SAT Math SAT Math Geometry and Measurement Similarity, Right Triangles, and Trigonometry Understand similarity in terms of transformations Triangles Types of Triangles

### Transcript

00:27

…maybe it was getting stir crazy and wanted a change of scenery.

00:30

Whatever the reason, this problem tells us that we must first rotate the sucker 90 degrees about the origin…

00:36

…and then reflect it across the y axis.

00:40

When we rotate the triangle about the origin,

00:42

that means that we have to picture the entire thing on a hinge…

00:46

…and that hinge is at zero, zero.

00:48

…we just have to imagine that pivot point, and swing the whole thing around from there.

00:53

When we do that, our triangle ends up here…

00:55

…with point C at (-2, -1).

00:59

And now the easy part. When we reflect a shape across an axis, all we do is flip it.

01:04

We can see that point C now sits at (2, -1)…

01:07

…which is choice E, our final answer.