O piesa lego are forma ca in figura AC=BD=2cm .
Calculati suprafata hasurata.

AC=BD = Diametru = 2R

D =2 cm ⇒ R =D/2=2/2=1 cm

R = 1 cm

Aria sector = (πR²u)/360; R =1cm; u =90°; Aria sector = (π× 1²×90)/360=π/4 cm²

Aria cerc = π × R² = π × 1² = π cm²

Aria hasurata = Aria cerc -Aria sector cerc = π -π/4=3π/4 cm²

aria hasurata este aria a 3/4 din aria unui cerc cu raza R=2/2=1cm

aria cercului=πR²=π*1²=πcm²

aria hasurata=3π/4 cm²