Thursday, June 13, 2013

Rumus bangun datar

Rumus keliling dan Luas Bangun Datar


Rumus Persegi
Keliling : 4 x Sisi
contoh : Sisi = 5 cm
Keliling = 4 x 5
= 20 cm

Luas : Sisi x Sisi
contoh : Sisi = 5 cm
Luas = 5 x 5
= 25 cm2

----------------------------------------------------------------------------------------------------------------------------------------Rumus persegi panjang
Keliling : 2 x (Panjang + Lebar)
contoh : Panjang = 6 cm
Lebar = 4 cm
Keliling = 2 x (6 + 4)
= 20 cm

Luas : Panjang x Lebar
contoh : Panjang = 8 cm
lebar = 5 cm
Luas = 8 x 5
= 40 cm2
----------------------------------------------------------------------------------------------------------------------------------------Rumus SegitigaKeliling : AB + AC + BC
Contoh : AB = 8 cm
AC = 10 cm
BC = 6 cm
Kelililng : 8 + 10 + 6
= 24 cm

Luas Segitiga : 1/2 x alas (BC) x tinggi AB
1/2 x 6 x 8
= 24 cm2
----------------------------------------------------------------------------------------------------------------------------------------

Rumus LingkaranKeliling lingkaran :22/7 x diameter atau 2 x 22/7 x jari jari

contoh : diameter =28 cm
jari jari = 2 x diameter = 28 : 2 = 14 cm
Keliling : 22/7 x 28
= 88 cm

Luas lingkaran : (22/7 atau 3,14) x jari jari
= 22/7 x 14 x 14
= 44 x14
= 616 cm2

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