Question

Which polygon is a concave octagon?

Answer 1

The polygon in option 3 is not octagon at all, it is heptagon (or 7-sided polygon).

A convex octagon has no angles pointing inwards. More precisely, no internal angles can be more than 180°.

When some internal angle is greater than 180°, it is concave.

In option 2 you can see that one angle is pointing inward, then this octagon is concave.

Answer: correct choice is B.

Answer 2

2nd one. it is concave because one of the side goes inside of the octogon.Its pretty easy tbh. Hope it helped.