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Geometry and Measurement Videos 87 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 1.3 Geometry and Measurement
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SAT Math 1.3 Geometry and Measurement. Find the length of CE.

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SAT Math 9.4 Geometry and Measurement 184 Views


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Description:

SAT Math 9.4 Geometry and Measurement

Language:
English Language

Transcript

00:03

Here’s your shmoop du jour, brought to you by swimming pools.

00:06

We’ve tried to swim a few laps, but we can’t quite get the hang of it.

00:10

The cue ball keeps getting in the way.

00:12

A deck 10 feet wide is built around three sides of a square pool.

00:17

The fourth side is adjacent to a long wall.

00:21

If the area of the deck is 740 ft2, what is the area of the pool?

00:28

Here are the potential answers...

00:32

Rather than just look at words on a page, it helps to visualize, so let’s… do so.

00:36

Here’s our pool. We have no idea yet how big it is.

00:39

And…here’s our deck. It surrounds the pool on three sides.

00:43

We know it’s 10 feet wide…

00:45

…so, let’s break this deck down a bit, into more manageable pieces.

00:48

Now we’ve got 5 distinct sections… and we're gonna label them…

00:52

The sections touching the pool are going to have an area of 10x, with x being the unknown length.

00:59

We’ve got three of those, so…3 times 10x, or 30x.

01:04

Now for the corner sections, those are DEFINITELY going to be 10 x 10.

01:08

Doesn’t matter how big the pool is.

01:09

We have 2 of those, or… 2 times 10 times 10. Which is 200 square feet.

01:16

Altogether then, we have 30x plus 200.

01:20

We can set that equal to the 740 square feet we’re given…

01:25

…subtract 200 from both sides to get 30x = 540…

01:29

…then divide both sides by 30 to get x = 18.

01:34

Option B is 18…but don’t fall for it!

01:37

We’ve got the measure of one side of the square pool… but we need to square it to get the pool’s area.

01:43

18 squared is 324… so the pool is 324 square feet.

01:49

Choice D and we're done.

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