Răspuns:
Explicație pas cu pas:
R=4cm
b)L=2πR=2π4=8π cm
c) daca AB=4 cm si AO=BO=AB=4 cm ⇒ΔAOB echilateral
∡AOB=60° ⇒arc mare AB=360°-60°=300°
d)A=πR²=π4²=16π cm²
e) 2πR.........................360°
x...............................300°
x=2πR·300°/360°=8π5/6=4·5π/3 cm=20π/3 cm