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SAT Math 5.2 Geometry and Measurement 253 Views


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Description:

SAT Math 5.2 Geometry and Measurement

Language:
English Language

Transcript

00:02

Here’s your shmoop du jour, brought to you by interlocking circles.

00:13

How many tangent lines can be drawn to exactly two circles in the picture below?

00:18

Here are the potential answers...

00:22

First up, let’s make sure we all know what a tangent is.

00:26

And no, it's not a funky kind of orange.

00:28

The one that connects at an arc or circle at exactly one point is a tangent.

00:38

The easiest way to solve this problem is to start by imagining that one of these circles isn’t even there.

00:45

Poof, it’s gone.

00:46

There are all sorts of tangent lines we can draw to one of these circles…

00:49

…but only two will hit both circles at exactly one point.

00:54

Now if we do the same with a different pair of circles, we get the same result.

00:59

Same deal with the final pair.

01:01

So…looks like we get 2 tangents times 3 possible pairings…

01:05

…for a grand total of 6 tangent lines.

01:07

And boom, we’ve got our answer – option D.

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