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### Course: Algebra 1>Unit 3

Lesson 2: Appropriate units

# Reporting measurements

We should think about the appropriate level of precision of different measurements in modeling problems. Created by Sal Khan.

## Want to join the conversation?

• Why are there so many different units to measure in math. Why can't we just use one?
(1 vote)
• There's a good reason we can't. let's say we only stick to using metres. Now, how would you measure the distance between planets in metres? it would be an incredibly large number which would be inconvenient to deal with. Hence, we use a different unit (like light years) to make our numbers smaller and manageable.
• Video: But then I say, is it exactly one centimeter?
Me: ......I guess I could do a little more.
Me: gets magnifying glass
Me: proudly It's ACTUALLY 1.1 cm. :D
Video:......IS THAT THE ACTUAL DIAMETER?
Me: ....Ur gonna make me get out the microscope -_-
Me: gets out the microscope
Me: FINE. IT'S 1.089 CM. PERIOD
Video: ...
Video: Are you sure?
Me: T_T

Just me-?
• Such hard work
(1 vote)
• Would you rather the slide be too long or too short?
• I would rather the slide be too long.
• Curiosities: Mount Wycheproof in Australia is the smallest peak in the world, at 42 meters above surrounding terrain and 147 meters above sea level. Mount McKinley in Alaska is the highest peak above surrounding terrain, at 6193 meters (higher than Everest at 5380m). Mount K2 is considered the hardest climb.
• But Sal, we could make a pile of snow at the base of the slide to prevent breaking any bones, right?
• it seems impracticable to build a seemingly super fun eight-thousand-six-hundred-and-eleven meter long slide that you need to trek up the steep icy slopes in order to ride.
Or maybe you could just build 8,611 meter staircase next to it.
• Or an elevator...
• if you were to build such a slide, wouldn't it actually be longer than the height of the mountain? since it's along the slope, not a tunnel through the mountain or something (ie Pythagoras theorum)
(1 vote)
• Yes, Exactly! Because the slope of the mountain is the hypotenuse, the longest leg of a triangle.