1. A certain tree measures 102.6 feet in circumference.
Show how to find the distance straight through the center of the tree(the diameter)
without measuring it directly, then find this value to the nearest tenth of a foot.
You're expected to know this formula: .
. . where is the diameter of the circle and is its circumference.
We are given: .
. . Substitute into the formula: .
Therefore: . feet.
2. Suppose a rope wrapped around earth at the Equator.
Then think of adding feet to the rope's length
so it can now circle earth at a distance feet above the Equator at all points.
a. Write an equation to model this situation.
b. Solve for .
c. How much rope do you need to insert if you want the rope
. . to circle earth 500 feet above the Equator?
Circumference formula: .
. . where = radius of the circle.
Let = radius of the earth (in feet).
Then the original rope has length feet.
The new rope has length . I hope you see why.
The difference of the two circumferences is .
. . .(a)
(c) .We want feet.
. . . Therefore: . feet.