Verified answer

Bonjour,

1° figure: 1/4 de cercle

(pir²)/4

(3,14 * 2,5²)/4 =>4, 91cm²

2° figure : 1/2 cercle

(3,14 * 2,5²)/2 => 9,81cm²

3° figure:

[(3,14 *2,5²) /  4] *3 => 14, 72 cm²

Verified answer

Aire de la 1ère figure :

(2,5^2×3,14)÷4

=(2,5×2,5×3,14)÷4

=19,625 ÷4

=4,90625 soit 4,91 cm^2

Aire de la seconde figure :

(2,5×2,5×3,14)÷2

=19,625÷2

=9,8125 soit 9,81 cm^2

Aire de la 3ème figure :

((2,5×2,5×3,14)÷4)×3

=4,91×3

=14,73cm^2

Formule :

Aire du cercle = pi×r^2(rayon)