Question

a designer needs to create perfectly circular necklace. the necklace each need to have a radius of 10cm. what is the largest number of necklaces that can be made from 1000cm of wire 1)15 2)16 3)31 4)32

Answer 1

1)15

The formula for the circumference of a circle is 2π x r
r must always be 10cm

2π x 10 = 62.8cm
This is how much wire is needed to make each necklace

1000/62.8 = 15.92
This is how many necklaces can be made, however since there are only 15 whole necklaces the answer is 15.

We are short 0.008cm to make the 16th one.

Answer 2

ok so find circumference of 1 neclace
C=2pir
r=10
C=2pi10
c=20pi

how many 20pi's make 1000?
20pi times x=1000
divide both sides by 20pi
xnecklaces=1000/20pi
xnecklaces=50/pi
aprox pi=3.14
xnecklaces=50/3.14
xnecklaces=15.915
round down since you can't sell 0.9 necklasce

15 is answer

1st option is correct