Persegi

Luas:

L = s × s = 5 × 5 = 25 cm²

Keliling

K = s × 4 = 5 × 4 = 20 cm

Persegi panjang

Luas:

L = p × l = 12 × 8 = 96 cm²

Keliling:

K = 2 × (p + l) = 2 × (12 + 8) = 2 × 20 = 40 cm

Segitiga

Luas:

L = ½ × a × t = ½ × 12 × 8 = 6 × 8 = 48 cm²

Keliling:

K = a + sisi miring + sisi miring = 12 + 10 + 10 = 32 cm

Layang-layang

Luas:

L = ½ × d1 × d2 = ½ × 24 × 40

= 12 × 40 = 480 cm²

Keliling:

K = 2 × (sisi miring 1 + sisi miring 2)

= 2 × (13 + 37) = 2 × 50 = 100 cm

Jajargenjang

Luas:

L = a × t = 12 × 6 = 72 cm²

Keliling:

K = 2 × (a + sisi miring) = 2 × (12 + 9)

= 2 × 21 = 42 cm

Trapesium siku-siku

Luas:

L = ½ × jumlah sisi sejajar × t

= ½ × (12 + 12 + 6) × 8

= ½ × 30 × 8 = 15 × 8 = 120 cm²

Keliling:

K = 12 + 10 + 6 + 12 + 8 = 48 cm

Lingkaran

Luas:

L = π × r² = 22/7 × 21 × 21

= 22 × 3 × 21 = 1.386 cm²

Keliling:

K = π × r × 2 = 22/7 × 21 × 2

= 22 × 3 × 2 = 132 cm

Belah ketupat

Luas:

L = ½ × d1 × d2 = ½ × 12 × 16

= 6 × 16 = 96 cm²

Keliling: K = s × 4 = 10 × 4 = 40 cm

Ini aneh, sebenarnya kalau sisinya sama semua harusnya diagonalnya juga sama, tapi yah sudahlah