The area of a circle is 641 ft2. What is the circumference, in feet? Express your answer in terms of

Step-by-step explanation:

Given

Area of a circle (A) = 641 ft²

Circumference (C) = ?

We know

πr² = 641

r² = 641 / 3.142

r² = 204

r = 14.28 ft

Now

Circumference

= 2πr

= 2 * 3.14 * 14.28

= 89.68 ft

Hope it will help :)

47

step-by-step explanation:

reduce the friction between its moving parts

step-by-step explanation:

in fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.