Lenght of arc DE

Question

Answer 1

The full circumference is 2πr where r is the radius. In your problem, r = 8 cm so the full circumference is:

2·π·8 = 16π

But your sector is only 125° not the full 360°. So just multiply the full circumference by 125/360:

Sector Length = 16π·(125/360) = 50π/9 cm ≈ 17.45 cm