Bonjour,
formule: Pir²
a)
pi4² => 16pi m²
3,14 * 16 =>50, 2 m²
b)
pi 32² => 1 024pi mm²
3,14* 1024 => 3 215, 4 mm²
c)
r = 6/2 = > 3hm
pi 3² => 9pi hm²
3,14 *9 => 28, 3hm²
d)
r = 5,6/2 => 2,8 dm²
pi * 2,8² => 7,84pi dm²
3,14 *7,84* => 24, 6 dm²
