pake cara pada nomor 11

ABE siku-siku di E
AB = 20 cm
AE = 12 cm
BE = √AB²-AE²
BE = √20² - 12²
BE = √400 - 144
BE = √256
BE = 16 cm
CE = 6 cm
BC = 16 - 6
BC = 10 cm
Luas segitiga ABE = Luas segitiga ACE + Luas segitiga ACB
BE x AE / 2 = AE x CE / 2 + AB x CD / 2
16 x 12 / 2 = 12 x 6 / 2 + 20 x CD / 2
192/2 = 72/2 + 20CD/2
96 = 36 + 10CD
10CD = 60
CD = 6,0 cm (C)
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