C because 3 is the intercept and -2 is the slope
Remember that complementary angles add to 90 degrees.
so therefor, you can find the complement of m<A by solving
90 - 77 = A
A = 13 degrees
^^^ This explains the second part.
The compliment of a compliment can be found by subtracting the known compliment from 90 :)
Answer is 5 because the other sides are 9 each
We conclude that the sum of the first 8 terms of the arithmetic sequence is 17/5.
<h3>
How to get the sum of the first 8 terms?</h3>
In an arithmetic sequence, the difference between any two consecutive terms is a constant.
Here we know that:

There are 7 times the common difference between these two values, so if d is the common difference:

Then the sum of the first 8 terms is given by:

So we conclude that the sum of the first 8 terms of the arithmetic sequence is 17/5.
If you want to learn more about arithmetic sequences:
brainly.com/question/6561461
#SPJ1