A regular hexagon is shown below. Find the value of x.
(11x + 21)°

x=9

Step-by-step explanation:

The expression is for the interior angle of the hexagon; one interior angle is equal to .

Since an interior angle of a hexagon measures 120°, we have the equality

.

Now it is just a matter of solving for  

11x=120-21

11x=99

x=99/11

x=9

answer: the answer is one of

step-by-step explanation:   we are given to write a proper fraction where the whole is divided into an even number of equal parts less than ten, and an odd number of those parts exist.

an even number less than 10 may be one of 2, 4, 6 or 8. so, the whole may be one of these four evens.

now, an odd number of these parts must exist, so the numerator must be an odd number, one of 1, 3, 5 or 7. it cannot be 9 because then the fraction will become improper.

thus, our fraction may be one of the following

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.