Answer: It's 6
Step-by-step explanation:
Solution
Part A
The general form of the n-th term = a + (n-1)d
Here we are given the 8th term A8 = 28
, common difference (d) = 6
A8 = a + (n - 1) 6
28 = a + (8- 1)6
28 = a + 7*6
28 = a + 42
a = 28 - 42
a = -14
Part B
n-th term is 760. a = -14 and d = 6.
Plugging in the values in the general form, we get
760 = -14 + (n -1)6
760 = -14 + 6n - 6
760 = -20 + 6n
6n = 760 + 20
6n = 780
Dividing both sides by 6, we get
n = 780/6 = 130
The value of n is 130
Hi there!
In order to figure out the total measures of interior angles of a polygon, you can use this equation: (n-2) * 180.
#1 - First, let's figure out the total measure of interior angles
WORK:
(6 - 2) * 180 = 720
Next, we can add up all of the values and set it equal to the total interior angle measures. Since the two unknown angles are congruent, we can show those as 2x.
WORK:
90 + 149 + 103 + 108 + 2x = 720
2x + 441 = 720
2x = 279
x = 139.5 degrees
#2 - In any polygon, the value of the exterior angles always adds up to 360. Using that, we can create another equation, adding up the values and setting it equal to 360. For the one interior angle that is there, we need to find it's supplementary angle.
WORK:
43 + (180 - 106) + 11x + 12x + 37 + 17x + 50 + 12x = 360
52x + 204 = 360
52x = 156
x = 3 degrees
Hope this helps!! :)
If there's anything else that I can help you with, please let me know!