Answer:

Step-by-step explanation:
The recursive rule tells you the initial term of the sequence is a1 = -3, and the common difference is d=7. (7 is the value added to one term to get the next term.)
Putting these values into the formula for the explicit rule gives ...
an = a1 +d(n -1)
an = -3 + 7(n -1)
Answer: 102 degrees
Step-by-step explanation:
This is an isosceles triangle because two of the sides are the same length which means that two angles are congruent as well.
180-(2(39))
=180-(78)
=102