5. Perhatikan gambar berikut (kiri), tentukan keliling dan luas arsiran! phi= 3,14

Jawab:

Penjelasan dengan langkah-langkah:

Segitiga besar

P sisi tegak  = √10²-6² = √100-36 = √64 = 8 cm

Segitiga kecil:

P = √5²-4²=√25-16 =√9 = 3 cm

Kll 1/2 lingk = 1/2 x πD  ; D = 3cm

= 1/2 x 3,14 x 3

= 4,7 cm

Kll Arsiran = 6+6+4,7 = 16,7 cm

Luas Arsiran = L1 – (L2+L3)

L1 = 1/2 x 6 x 8 = 24

L2 = 1/2 x 3 x 4 = 6

L3 = 1/2 x 1/4πD² = 1/2 x 1/4 x 3,14 x 3² = 3,53

L Arsiran = 24 – (6+3,53) = 14,47 cm²

w =2×57 = 114°

2y = 180-w = 180-114 = 66

y=66/2= 33°

x = 180-57-22-2y

  = 180-57-22-66

  = 35°

z = 180-57 = 123°

jadi:

w =114°

x =35°

y =33°

z =123°