no 7 , 8 dan 9 ... pakai cara

7.) L∆ = 1/2 . alas . Tinggi
L∆ = 1/2 . 20 . 10
L∆ = 10 . 10
L∆ = 100 cm^2

L jajargenjang = alas . Tinggi
L (j) = 20 . 11
L (j) = 220 cm^2

L seluruhnya = 100 + 220 = 320 cm^2


8.) L∆ = 1/2 . Alas . Tinggi
L∆ = 1/2 . 15 . 12
L∆ = 15 . 6
L∆ = 90 cm^2

L persegi = Sisi . Sisi
L persegi = 15 . 15
L persegi = 225 cm^2

L seluruhnya = 90 + 225 = 315 cm^2


9.) L trapesium = 1/2 (ab + dc) t
L (t) = 1/2 (10 + 5) 2
L (t) = 15 cm^2

L persegi panjang = p . l
L (Pp) = 5 . 2
L (Pp) = 10 cm^2

L seluruhnya = 15 + 10 = 25 cm^2