Respuesta :

area of a circle: πr²

Data:
diameter:  21 cm
radius=diameter/2=21 cm/2=10.5 cm

area of this circle: π(10.5 cm)²=110.25π cm²  (≈346.36 cm²)

Answer: area=110.25π cm²
tristanluedke
The area of a circle with a diameter of twenty-one is roughly 346 or 346.36 to be exact.

- Divide the diameter by two to find the radius.

- Square the radius & Multiply by Pi