Wednesday

April 23, 2014

April 23, 2014

Posted by **Remmy** on Wednesday, November 28, 2012 at 1:25am.

2) A running track 4 m wide goes around a soccer field that is twice as long as it is wide. At each end of the soccer field the track is a semi-circle with inner radius r. Find a formula for the area of the track in terms of *pi and r.

3a) Suppose that you plan to run once around the track described in the problem above. If you stay 0.5 m from the inner edge of the track, how far will you run? (Hint: The circumference of a circle is *2pir. Your answer will be in terms of *pi and r.)

3b) Suppose that a friend stays 0.5 m from the outer edge of the track. How much farther does your friend run than you do?

*pi = 3.14 or 22/7

- Algebra -
**Reiny**, Wednesday, November 28, 2012 at 10:49amoriginal square ---- > let each side be x

new sides are x-3 and x-5

so x^2 - (x-3)(x-5) = 185

x^2 - (x^2 - 8x + 15) = 185

8x - 15 = 185

x = 200/8 = 25

check:

original square was 25 by 25 , area = 625

new rectangle was 22 by 20 , area = 440

difference = 625-440 = 185

All looks good

2. I will let you do this one.

Hint: let the width of the soccer field be 2r, that way you can label the radius of the ends as r

The two semi-circular ends will constitute one whole circle. So the circular part of the track will be the "ring" formed by two circles, one of radius r, the other of radius (r-4)

**Related Questions**

Math help, please - A corner lot that originally was square lost 185 m of area ...

math - a corner lot that was originally square lost 185m^2 area when one of the ...

triganometry - A landscape architect is designing a triangular garden to fit in ...

Physics 1112 Electric charge - As shown in the figure, a square has sides of 8.0...

algebra 2 - Darla is building a new desk. To make sure she had made a square ...

algebra 2 - Darla is building a new desk. To make sure she had made a square ...

algebra - Darla is building a new deask. to make sure she had made a square ...

Physics - On the lower left corner of a square is a fixed charge qLL = 1.5x10^-9...

Geometry - How do I figure out the area and perimeter of a square if all I know ...

algesebra - Darla is buildig a new desk. To make sure she made a square corner...