Arc Length & Area of a Sector

POINT

おうぎ形の弧の長さと面積は、円全体に「中心角÷360」をかけて求めます。半径と中心角を最初に確認しましょう。

Example

Find the arc length and area of the following sector.

Practice

Find the arc length and area of each sector.

Radius = 6 cm, central angle = 60°

Arc length: 2π cm

Area: 6π cm²

Radius = 8 cm, central angle = 90°

Arc length: 4π cm

Area: 16π cm²

Radius = 10 cm, central angle = 120°

Arc length: 20π/3 cm

Area: 100π/3 cm²

Radius = 12 cm, central angle = 150°

Arc length: 10π cm

Area: 60π cm²