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SAT Math 8.4 Geometry and Measurement 327 Views
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Description:
SAT Math 8.4 Geometry and Measurement
Transcript
- 00:03
Here’s your shmoop du jour, brought to you by shadows.
- 00:06
Peter Pan is offering a $500 reward for his, in case you see it.
- 00:11
A person 5 ft. 10 in. tall casts a shadow 10 ft. 2 in. long.
- 00:17
Approximately how tall is a tree that casts a 15 ft. 6 in. shadow?
- 00:24
Here are the potential answers...
Full Transcript
- 00:29
Okay, we’ve got one fella whose shadow is nearly twice as long as he is tall.
- 00:34
So, now in roughly the same spot…
- 00:37
…is a tree whose shadow has got our hero’s shadow beat by over 5 feet.
- 00:42
And we want to figure out… how tall is this tree?
- 00:44
Well, what we have here is a simple ratio.
- 00:47
The person’s five feet and 10 inches is to his 10 foot, 2 inch long shadow…
- 00:52
…as “x” is to the tree’s 15 foot, 6 inch shadow.
- 00:57
This problem is going to be a heck of a lot easier to deal with if we convert everything
- 01:00
to inches, so…let’s do that.
- 01:03
70 inches is to 122 inches…
- 01:05
…as x is to 186 inches. We’ll set everything up as a fraction…
- 01:11
70/122 = x/186…
- 01:15
…and now we can just cross-multiply.
- 01:17
122x = 13,020
- 01:20
Divide both sides by 122 and x = 106.72.
- 01:26
Now, remember…we converted everything to inches, so now we have to convert back to feet.
- 01:31
106.72 divided by 12 is 8.89 feet…
- 01:34
…which is option C.
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