Cut the largest circle with a rectangular piece of paper 10 cm long and 8 cm wide, The radius of this circle is () cm, the perimeter is (), and the area is ()

Cut the largest circle with a rectangular piece of paper 10 cm long and 8 cm wide, The radius of this circle is () cm, the perimeter is (), and the area is ()

The radius of this circle is (4) cm, the perimeter is (25.12 cm), and the area is (50.24 square cm)