caranya dan jawabanya

Bab Bangun Datar
Matematika SMP Kelas VII

14] jajar genjang
AB x BE = AD x FB
FB = 10 x 8 : 16
FB = 5 cm → D

15] jajar genjang
luas = AD x FB = 288
AD = 288 : 18
AD = 16 cm

keliling = 2 x (AD + AB)
keliling = 2 x (16 + 36)
keliling = 104 cm → A

16] layang - layang
keliling = 2 x (AD + DC) = 54
AD + 17 = 54 : 2
AD = 27 - 17
AD = 10 cm

DO = √(AD² - OA²)
DO = √(10² - 6²)
DO = √(100 - 36)
DO = 8 cm

CO = √(DC² - DO²)
CO = √(17² - 8²)
CO = 15 cm

luas = 2 x 1/2 x DO x AC
luas = 8 x (6 + 15)
luas = 168 cm² → A