Answer:
Step-by-step explanation:
The first term is -43.
Explanation:
an = a + (n - 1)d
a12 = a + 11d = 56, first equation
a21 = a + 20d = 101, second equation
Subtract the second equation from the first equation, cancelling +a and -a
11d - 20d = 56 - 101
-9d = -45
d = 5
Subtitute d into the first equation
a + 99 = 56
a = -43
a refers to the first term, hence the first term is -43.
A) All triangles add up to 180° so when given two angles, add those up and subtract them from 180° . That will give you the missing angle.
3-5) When you do A above, and receive the measurement of angle 1, it will also equal 2 and you can repeat A for missing angle 3
6-8) Find the missing angle next to 1, and then subtract that from 180°. That number is the answer for 1. 2 is 55 as its a complimentary (i think thats the right term) angle. Which means it is on the opposite side of an angle. I don't remember how to find 3 however, its been a few years since I've done triangles.
Answer:
its a
Step-by-step explanation: