For a regular polygon with n sides, interior angle
= [(n-2) × 180°]/n
So, interior angle of this regular heptagon shape
= [(7 - 2) × 180°]/7
= (5 × 180°)/7
= 900°/7
= (900/7)°
= 128.571° [approximately]
The sum of the first five terms is 11/2
<h3>How to determine the sum?</h3>
The series is given as:
1/2, -1,2,-4…
Calculate the common ratio of the series using
r = -4/2
Evaluate
r = -2
The sum is then calculated as:

This gives

Evaluate

Evaluate

Hence, the sum of the first five terms is 11/2
Read more about series at:
brainly.com/question/11346378
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1+2=3. 4/10+2/10=6/10. 3+ 6/10=3 6/10
.10 I hope that that helps you :)