Frank jogs in a circular garden every day. The ground measures 5 feet from the center to the inner circle and an extra 3 feet from the inner circle to the outer circle. If Frank jogs around the outer circle twice, how much distance does he cover?

Question

anonymous · Answer

@elevel17

anonymous · Answer

@KenLJW

anonymous · Answer

@mathstudent55

mathstudent55 · Answer

|dw:1369722306850:dw|

primeralph · Answer

tell them to get a treadmill. Quite cheap nowadays.

mathstudent55 · Answer

|dw:1369722415957:dw|

mathstudent55 · Answer

The radius of the outer circle is 8 ft.
You need the circumference of the circle.
C = 2(pi)r
Plug in 8 ft for r. Then multiply the result by two since Frank goes twice around the circle.

anonymous · Answer

hmmm
well i got 50.24 but i think its asking for something else couse the answers possible are
A. 2p(5 + 8)
B. 2p(10 + 16) 
C. p(8 – 5) 
D. 2p(8 + 8)

anonymous · Answer

O! so its A!

anonymous · Answer

Thanks for the help been working on this problem forever

mathstudent55 · Answer

It's D

anonymous · Answer

how?

mathstudent55 · Answer

C = 2(pi)r = 2 *pi * 8 for one lap
Two laps are 2pi8 + 2pi8 = 2pi(8 + 8)

whpalmer4 · Answer

$2\pi(5+8)$ represents the distance around the inner circle once and the outer circle once...

anonymous · Answer

but doesnt the 2 already count the 8+8?

whpalmer4 · Answer

No, the formula for the circumference of a circle is $C = 2\pi r$.

mathstudent55 · Answer

the 2 is from 2(pi)r, the formula for the circumference of a circle

mathstudent55 · Answer

C = 2(pi)8 is only onle lap around the outer circle.

anonymous · Answer

ooooo ok