If a pentagon is regular, then all of the sides are the same length. This means that

So, if
, the lengths of the sides evaluate to

So, all the sides of the pentagon are 21 units long, and AB is 21 units long as well, because all sides are the same length.
Average speed is the distance traveled by an object in total and divided by the amount of time an object covers the distance. The formula is -
Average speed = total distance traveled / total time taken
= 68km+64km / 2 hrs.+3hrs.
= 132km / 5hrs.
= 26.4km/hr.
Therefore, the train's average speed is 26.4km/hr.
9 divided by g to the power of 3
Ertex angle:: x degrees
<span>base angle: x+15
</span>