Đáp án:
BG=19mm,AC=48mm,AH=8mm,HK=18mm
KC=22mm,EH=16mm,KD=23mm
SABC=12.BG.AC=12.19.48=456 (mm2)
SAHE=12AH.HE=128.16=64 (mm2)
SDKC=12.KC.KD=12.22.23=253 (mm2)
SHKDE=(HE+KD).HK2=(16+23).182=351 (mm2)
Do đó
SABCDE=SABC+SAHE+SDKC+SHKDE=456+64+253+351=1124(mm2)
Vậy SABCDE=1124(mm2)