Math: Geography Problem

[gotpho]

I have no idea how to approach this problem.

Radius of earth is 3963 mi

The latitude of Lima, Peru is 12 degree south. About how far from Lima is the south pole?

I'm guessing you draw a 12 degree angle from the center in the 4th quadrant of a graph. Thus, you get a triangle but what would be the next step?

[freeztar]

How many degrees of latitude are there?

Btw, what level math are you taking?

[Turtle]

Originally Posted by gotpho

I have no idea how to approach this problem.

Radius of earth is 3963 mi

The latitude of Lima, Peru is 12 degree south. About how far from Lima is the south pole?

I'm guessing you draw a 12 degree angle from the center in the 4th quadrant of a graph. Thus, you get a triangle but what would be the next step?

Well, you have some idea. I'm thinking that if the radius is 3963, then the circumference is 3963 * 2 * pi, and then since there are 360 degrees in a circle, I'm thinking divide circumference by 360, giving you miles-per-degree. Then, finish up by.... figuring from there.

[Buffy]

Of course those solutions are "as the crow flies" and the answer may actually be asking for "as the gopher digs"....

Dig the well before you are thirsty,
Buffy

[Turtle]

Originally Posted by Buffy

Of course those solutions are "as the crow flies" and the answer may actually be asking for "as the gopher digs"....

Dig the well before you are thirsty,
Buffy

True enough; however, the crow flies as the geography goes, and the gopher digs as the geometry goes.

What class is this for gotpho?

[gotpho]

Originally Posted by freeztar

How many degrees of latitude are there?

Btw, what level math are you taking?

This was for Precal.

I happened to have solve it.

[freeztar]

Originally Posted by gotpho

This was for Precal.

I happened to have solve it.

Good for you!

How did you approach it? If you post your answer (with work), one of us can check it for you.

[gotpho]

Well I realized you could find the arc length

s=r * radian of angle

but using 12 degree wasn't right. I realized that you had to subtract 90 degree from 12 to get the angle between the two points.

so the final formula

S=r*(90-12)*pie/180

[Turtle]

Originally Posted by gotpho

Well I realized you could find the arc length

s=r * radian of angle

but using 12 degree wasn't right. I realized that you had to subtract 90 degree from 12 to get the angle between the two points.

so the final formula

S=r*(90-12)*pie/180

Mmmm...my method wasn't far off. I get 5395.052507 miles using your equation, and 5810.056546 miles from mine. A variance of ~ 1%. (I used 1.314159 for pi)

PS hold on....

OK I get 5395.052507 for mine too; I subtracted 12 from 90 wrong and used 84 instead of 78.

Resume your normal activities.