Area error in Google Earth Engine

Question

I'm trying to calculate the area of multiple classes within Lake Manyara in my map. The overall area of the lake is approx 38,000 hectres (380km) (worked out by creating a polygon and calculating its area). However when the areas of the different classes are calculated and added together, it equals over 68,000 hectres which is clearly incorrect. I already put a feature over my lake to ensure no other lake's classes are added on, yet it is still incorrect. Can someone explain how to overcome this?

Here is my link containing the total and classed areas: https://code.earthengine.google.com/6fec6f9208d132a3f1e974217fe7cfe0

Answer 1

A couple problems, you've got a duplicate polygon variable, which is confusing things. Second, it looks like you're counting the lake area twice (i.e. the lake) band shouldn't be added to the sum. Pardon me if I've misunderstood.