As front passed,the temperature changed steadily over 6 hours. altogether it changed -18 degrees. what was the change in temperature per hour for the 6 hours. explain.

The temperature changed steadily over the 6 hours, which means that it changed the same amount of degrees every hour.  It changed -18 degrees in 6 hours. 
Divide the temperature change by the number of hours.
-18 ÷ 6 = -3
The change in temperature per hour is -3°.

A. No, because the arcs do not have the same measure.

Step-by-step explanation:

Two arcs can be said to be congruent when the length measure of the two arcs are the same and not necessarily the degree measure. This implies that two arcs can have the same degree measure measure but their length may not be the same.

If two arcs have the same measure in one circle, therefore we can say they are congruent or if they have the same measure in congruent circles respectively, they are congruent.

In the two circles given above, although we are not told if both circles are congruent, however, since both arcs have different degree measure, both arcs cannot be congruent.