To give a bit more detail on the tip chord............

Tip shape causes some people confusion. For example, me, back when I first started messing with this stuff.

You can often simply measure the chord as far out as the LE and TE are still straight. Using that as the tip chord works ok for most applications.

And you can almost always look at the planform of the wing and decide what area is tip area and where that starts. If you think about it, that tip area could be considered to be in a "box" that'd be there if the wing LE and TE went straight instead of curving around that silly tip, right. So think about how much area that tip shape fills up in that imaginary box. And if it appears to be about half, then estimate that into your figuring. You won't be exactly right, but that type of estimation will give you better figures for area, span, and taper ratio than you'll need.