diameter... junior high question?

its been over 20 years for me ! I forget...divide 84 by 3.14

well what uve done is basically made that 84 inch rope into a circle with a perimeter of 84 inches.

To find the diameter, ud have to work backwards using the perimeter of a circle formula

which i believe is Pi*Diameter

so....

84 = Pi*D

D=84/Pi

if its 42 inches then..

D=42/Pi

1)

Well, you know the circumference of the circle - 84 inches!

C = 2(pi)r

84 = 2(pi)r

r = 13.369 (approx.

Now, you have the radius, just multiply by 2 to get the diameter.

Diameter = 26.738 (approx)

2)

Same concept applies.

42 = 2(pi)r

r = 6.685 (approx.)

Diameter = 13.139 (approx).

circumference = 2 * pi * r

circumference / pi = 2 * r = diameter

circumference / diameter = pi

circumference / pi = diameter

the circumference of the circle is

C= π * d

so

d = C/π

If the rope is 84 inches long then

d = 84/π

d = 26.74 inches.

If the rope is 84 inches long then

d = 42/π

d = 13.37 inches.

Just divide the circumference by pi and that is your diameter.

diameter is 42"

diam 84/pi

half it ... 42/pi