Is it possible to draw a rectangle and then add extra corners?

I want to draw a vertical rectangle but the bottom corners will be closer to each other than the top two.

Similar to a triangle at the bottom of a rectangle but instead of a point it'll be a flat line. 

Yes it's very easy to do.

Draw a rectangle using the rectangle tool then choose Path>Object to path

Using the node tool drag a selection around the two bottom nodes of the rectangle path.

Click twice on the 'Insert new nodes' button on the far left of the toolbar. 

You then have 4 nodes at the bottom. Select and delete the far left and far right node.

The drag select all the nodes of the shape, and click the 'make selected nodes corner' icon on the node tool bar.

Done.

Thank you! 

Here's a slightly different approach:

1. Draw a rectangle.
2. Path > Object to Path.
3. Use the Node tool (F2) to move the bottom nodes. Hold Ctrl to force them to move horizontally.
4. ALTERNATIVELY, if you want the bottom two nodes equally spaced around the centre line, drag a selection box around them using the Node tool, then use the "<" and ">" keys to move them towards/away from each other.

For reference, the shape you're describing is called a trapezium (or trapezoid in North America).

Thanks for the reply @Xa, I think I wasn't too clear in my description.

I meant like a rectangle with a triangle like shape connected at the bottom so a shape with 6 angles.

I have found a way to add extra corners now.