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SAT Math 1.4 Geometry and Measurement. If the sides of a square increase in size by 25%, what happens to the area of the square?
SAT Math 1.5 Geometry and Measurement. How many jars of paint will Sierra need?
SAT Math 7.5 Geometry and Measurement 184 Views
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Description:
SAT Math 7.5 Geometry and Measurement
Transcript
- 00:03
It's a bird! It's a plane! It's Shmooperman...guy.
- 00:08
A fly is flying around this square board.
- 00:10
The length of the board is 36 centimeters.
- 00:13
If each of the lines is 1 centimeter thick, what is the probability that the fly will land on a line?
- 00:20
Round your answer to the nearest percent.
Full Transcript
- 00:22
Here are the potential answers...
- 00:27
It’s not like flies lead the most exciting lives. Maybe this is just its way of telling
- 00:30
us that it’s… “board?” All right, so we’re told that each line
- 00:35
on this board is 1 centimeter thick.
- 00:36
Okay, so we’ve got this board that’s 36 centimeters long and 36 centimeters wide.
- 00:42
We’re looking for the ratio of space taken up by lines to the space taken up by…emptiness…
- 00:47
…so the first thing we should do is probably count up these lines, eh?
- 00:51
We’ve got seven from top to bottom…
- 00:53
…and another seven from left to right.
- 00:55
That’s 14 lines total.
- 00:57
If each line is 36 centimeters long…which this problem tells us it is…
- 01:02
…then we take 36 times 14, for a total of 504 centimeters.
- 01:06
But hold your horses.
- 01:08
What about all those places where the lines overlap?
- 01:11
Yeah, we’ll have to subtract those points from our total.
- 01:14
We have 7 lines criss-crossing another 7 lines, which gives us 49 total points of intersection.
- 01:18
504 minus 49 equals 455…which is how much space the one centimeter thick lines taken up.
- 01:26
To get the total area of the board, we just take 36 times 36… which comes out to 1,296.
- 01:33
Now we need our percentage…so we take 455 divided by 1,296…
- 01:39
…and wind up with 35 percent. Answer B.
- 01:42
Unfortunately for our hero, this board also happens to be a popular hang-out spot for Franny the Frog…
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