Studi validasi pengukuran persen lemak tubuh berdasarkan pengukuran antropometri dengan golden standard bioelectrical impedance analysis di SMA Al-Azhar 3 Jakarta tahun 2017 = Validation study of percent body fat measurement using anthropometry with bioelectrical impedance analysis (BIA) as a golden standard in senior high school student of Al-Azhar 3 Jakarta, 2017