Jawab:
Luas trapesium kecil (yang A) = 72 cm²
Luas trapesium besar (yang B) = 162 cm²

Penjelasan dengan langkah-langkah:
Diketahui:
a = 6 cm, b = 12 cm, c = 10 cm
B = 18 cm
Perbandingan sisi
a/A = b/B = c/C
6/A = 12/18
A = 6×18÷12
A = 9 cm
6/9 = 10/C
C = 9×10÷6
C = 15 cm

Cari tinggi trapesium kecil (t)
t² = c² - (b-a)²
t² = 10² - (12-6)²
t² = 10² - 6²
t² = 100 - 36
t² = 64
t = √64
t = 8 cm

Cari tinggi trapesium besar (T)
t/T = a/A
8/T = 6/9
T = 8×9÷6
T = 12 cm

∴
Luas trapesium kecil (yang A)
(a+b)×(t/2) = (6+12)×(8/2) = 18×4 = 72 cm²

∴
Luas trapesium besar (yang B)
(A+B)×(T/2) = (9+18)×(12/2) = 27×6 = 162 cm²

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