An octagon is not a quadrilateral because it has eight sides.

Answer 1

Greetings...Leonard S. Hope you had a great weekend.

Is this a Geometry proof?

Is the question...the problem asking you to proof this statement?

If this is...here...I'll help you get started....

Statement/Given Reason/Proof

1. A quadrilateral is a polygon 1. Definition of a polygon
2. An octagon is an 8-sided polygon 2. Definition of an octagon
3. A quadrilateral is a 4 sided polygon 3. Definition of a quadrilateral
4. Okay...now the rest you can do to prove with an octagon is a quadrilateral or NOT quadrilateral

Let me now if you need any further assistance.

Respectfully

JG