Respuesta :

Radius 12 units,  area = π(12)² = 452.16 unit²

Diameter 16.8 units, area =  π(8.4)² = 221.5584 unit²
 
Radius 3.4 units, area = π(3.4)² = 36.2984 units²

Diameter 10 units, area =  π(5)² = 78.5 units²

Supernova
Area of a circle: πr²
To find the area if you have the diameter, do 1/4πd².


1) radius: 12 units ⇒ π12² = 452.16 square units

2) diameter: 16.8 units ⇒ 1/4π16.8² = 221.5584 square units

3) radius: 3.4 units ⇒ π3.4² = 36.2984 square units

4) diameter: 10 units ⇒ 1/4π10² = 78.5 square units