Question

VA ROG,DAU 100 DE PUNCTE SI COROANA IMPORTANT REPEDE!!!​

Answer 1

5)

P = 80 => L = 80 : 4 = 20 cm

∡B = 60°  } => ΔABC = echilateral => AC = 20 cm

BA = BC

BO² = BC² - OC²

BO = √400 - 100 = √300 = 10√3 cm

BD = 2BO = 20√3 cm

6)

AD || BC

AC = bisectoare } => ∡BCA = ∡BAC = (180°-120°) : 2 = 30° =>

ΔBAC = isoscel => BC = AB = 12 cm

Duc BE ⊥ AD

Δ ABE avem ∡EAB = 60° => ∡ABE = 30° => T30° => AE = AB/2 = 6 cm

DA = 2·AE + DC = 2·6 + 12 = 24 cm

P = AB + BC + CD + DA = 3·12 + 24 = 36 + 24 = 60 cm