Concave and Convex Quadrilaterals Examples

Is the figure shown a concave or convex quadrilateral?

If we draw in the two diagonals, we'll see that they both lie on the inside of the quadrilateral. That means no cavity, no cave. So if it's not concave, it's convex.

Is the figure shown a concave or convex quadrilateral?

It looks like a hungry monster with a wide-open mouth, ready to eat whatever comes its way. But, more importantly, one of its diagonals lies completely outside the bounds of the quadrilateral. That means it's concave.

Is the figure shown concave or convex?

When we draw the diagonals, we can see that both are contained completely within the figure. That means this guy is convex.