Answer:

Step-by-step explanation:
Given that , the sum of the first nine terms of an arithmetic series is 162 and the sum of the first 12 terms is 288.

<h3>
<u>Related</u><u> </u><u>Infor</u><u>mation</u><u> </u><u>:</u><u>-</u><u> </u></h3>
• The sum of n terms of an AP is
• nth term of an AP is given by ,

Answer:
a quadrilateral is a four sided shape that has four straight sides
8+(x/-9)=9 subtract 8
x/-9= 1 multiply by -9
x= -9
Knowing the squareroot of 81 is 9, we can easily know that square root of 83 is close to 9.
9 to the closest tenth is 10.
Hope I helped :)