12.6 cm²
Area formula: (A = πr²)
If the diameter is 4 cm.. then that would mean the radius is 2 cm because the radius is half of the diameter. So, we already know the radius.. we just have to find the circumference.
Circumference formula: (C = πd) or (C = 2πr)
Finding the circumference : 3.14 × 4 = 12.56 cm
So, we now have the radius and circumference.
Radius = 2 cm
Circumference = 12.56 cm
Finding the Area : 3.14 × 2 × 2 = 12.56 cm²
So, 12.56 rounded to the nearest tenth is 12.6 cm².
Hope this helped! :)