Network
L∆ABD = 1/2 x a x t = 1/2 x 6 x 8 = 24m²
L∆ADC = 150% x L∆ABD = 150/100 x 24 = 36m²
L.ABC = L.ABD + L.ADC = 24 + 36 = 60m²
L∆ABC = 1/2 x a x t
60 = 1/2 x BC x 8
BC = (60 x 2)/8 = 15m
CD = BC - BD = 15 - 6 = 9m
AC = (AB² + BC²) = (8² + 15²) = (289) = 17m
Jadi, K = AD + CD + AC = 10 + 9 + 17 = 36m
2. Amati gambar di samping. Tentukan keliling dan luas daerah yang diarsir. (pi = 3, 14).
Jawaban:
L daerah = L.persegi + L.1/4O + L.1/4O
L daerah = L.persegi + L.1/20
L daerah = (sxs) + 1/2 x π x r²
L daerah = (10 x 10)+ 1/2 x (3,14) x 5²
L daerah = 100 + 39.25
L daerah = 139.25 cm²
K daerah = r + r + ¼k.o + 1½ s + s + s + ½s+ ¼ k.o
K daerah = 2r + ½.k + 3s
K daerah = 2r + 1/2 x 2πr + 3s
K daerah = 2r + ½ x 2πr + 3s
K daerah = (2 x 5) + (3,14 x 5) + (3 x 10)
K daerah = 10 + 15,7 + 30
K daerah = 55,7 cm
