Fun Math - World's Circumference

How can our students take a full year of High School Geometry and not know the circumference of the world. Have we failed them in some way? Have we failed the education of our youth in some way? Shouldn't this be required knowledge like knowing who won World War II (WWII....on Jay Leno the other night...someone on the streets said that Hulk Hogan won WWII...lol).

How can you live on this earth and not be curious about how many miles there are around the world. I must admit that some of the better students do know it is about 3,000 miles between LA and NY (as the "crow flies"....i know all the babyboomers did that math in their head back the 1960's and 70's....3,000 miles and if i drive at 60 mph for 10 hrs a day...it will take me ?? how many days ?)

The guessing starts at 1,000,000 miles !! Some even say more than that....then i put up 100,000 miles on the board. Half the class says more, the other half less. And these are juniors in one of the best prep schools in Florida, over 600 on the Math SAT's and taking Honors Precalculus (forget the seniors in Honors Calculus they know even less than the juniors, and they will know even less after college).

So we establish that from the east coast to the west coast of the USA it is about 3,000 miles. (and many of these kids have flown to Colorado to go skiing...so they have at least have looked at a map of the USA even if it is just the one on the back of the airplane seat in front of you).

We go across the Pacific Ocean (a big ocean) and across China and into Russia. Across Europe and finally to the Atlantic Ocean and back to NY or Florida. (And these kids all have laptops and google earth !!)

Now most students in the class say it is LESS the 100,000 miles. We are making progress. And of course some student asks "is this on the next test ?" and "how is this important ?" and "I thought we were in Math class ?" and "This has nothing to do with PreCal ?" and "can i go to the bathroom ?" and "my mom is calling me on the cell, can i answer it ?"...the usual.

The Greeks in the BC (before Castro...no, before calculators...lol...no, no Before Christ) knew the world was round. It was obvious, just look at the sun and the moon. Just watch the sail of ships as they go over the horizon. In fact, the Greeks had determined that the circumference of the earth was actually 25,000 miles !!

They did some measuring using Euclidean Geometry of parallel lines and determined the ratio of 7 degrees/ 360 degrees was equal to 500 miles/ circumference of the World.

7/360 = 500/ Circum.

like Sherlock Homes would say..."elementary my boy, elementary"

So why do our students not know this as they prepare to graduate. And it gets worse for the general public. I taught adult math at the University for 30 years and i can tell you that adults do NOT even know that A = pi radius square. Even worse, they do not know how to find the area of a triangle. Mainly because they memorized some formula rather than understanding the the triangle occupies half the rectangle and every one knows the rectangle is width times height. But i have digressed.

So indeed the World's circumference is just 25,000 miles and Disney was correct when he sang "It's a small world after all".

Now living in Florida one should know that the Space Shuttle travels at about 17,000 miles per hour. So it takes the Space Shuttle only about 90 mins to make an orbit. When it says we can not land at the Cape, we will try on the next go around, i always thought that meant 1 or 2 days. But what it really means is we will be back in LESS then 2 hours !!