Answer:

Step-by-step explanation:
we know that
The formula to find the sum is equal to

where
a1 is the first term
an is the last term
n is the number of terms
In this problem we have



substitute the values in the formula

Answer:
x=135°
Step-by-step explanation:
45°- 180°=135x
90
55+65=120
there are 3 numbers and when you divide them it makes 70.
70 x 3 = 210
210 - 120 = 90
55 + 65 + 90 = 210
210 / 3 = 70
Answer:
576 ways
Step-by-step explanation:
There are 4 choices for the column of pawn in the 1st row
There are 3 choices for the column of pawn in the 2nd row,
There are 2 choices for the column of pawn in the 3rd row, and
There is 1 choice for the column of the pawn in the 4th row
Which gives a total of 4! = 24
Also, the pawns are distinct, so there are 4! ways to place them in these chosen positions;
4! = 24
So, there are 24 * 24 possible ways
= 576 ways