tolong bantu nomor 21 beserta caranya

K = AB + BC + CA
44 = AB + 20 + 13
44 = AB + 33
11 = AB

OB = OA + AB
= 5 + 11
= 16 cm

CO² = BC² - OB²
CO² = 20² - 16²
CO² = 400 - 256
CO² = 144
CO = √144
CO = 12 cm

L segitiga besar (BOC)
= ½ × a × t
= ½ × 16 × 12
= 96 cm²

L segitiga kecil (AOC)
= ½ × a × t
= ½ × 5 × 12
= 30 cm²

L segitiga ABC
= L segitiga besar - L segitiga kecil
= 96 - 30
= 66 cm²

Keliling = AB + BC +AC
44 = AB + 20 + 13
44 = AB + 33
AB = 44 - 33 = 11 cm

OB = OA + AB = 5 + 11 = 16 cm

Tinggi segitiga
= √BC²-OB²
= √20²-16²
= √400-256
= √144
= 12 cm

Luas segitiga ABC
= a × t/2
= 11 × 12/2
= 66 cm