how to calculate the area of pixels (hectares) by region

[astyapradipta]

I'm currently trying to use NDBI.
when I was about to calculate the built-up area, I didn't know what to do next
how to calculate the area of pixels (hectares) for each area that has been cut using administrative boundaries?

`#NDBI
ndbi = swir.subtract(nir).divide(swir.add(nir)).rename('NDBI se2')

ndbiparam = {'min':-1, 'max':1, 'palette':['green','yellow','red']}
Map.addLayer(ndbi, ndbiparam, 'NDBI temanggung 2022')
ndbic_mask = ee.Image(1).mask(ndbi.gte(-.01).gte(1));
ndbiparamc = {'min':-1, 'max':0, 'palette':['white','black']}
ndbic= ndbic_mask.clip(tmg)

import geemap
map = geemap.Map()
map.centerObject(tmg, 10)
map.addLayer(ndbi.clip(tmg), ndbiparam, 'NDBI temanggung 2022')
map.addLayer(ndbic,{}, 'bangunan')
map.addLayer(tmg,{},'temanggung')
map.addLayerControl()
map`