Use a compass. Draw a circle with radius 3 cm.
Two circles have the same centre. Their radii are 5 cm and 10 cm. Another circle lies between these circles. Give two possible diameters for this circle.

Find the radius of a circle with the diameter of 7.8 cm.
Find the radius of a circle with the diameter of 8.2 cm.
Find the radius of a circle with the diameter of 10 cm.
Find the radius of a circle with the diameter of 25 cm.
Is it possible to draw two different circles with the same radius and diameter? Why or why not?
Calculate the circumference with the radius of 6 cm.
Calculate the circumference with the diameter of 18m.
Calculate the circumference a wheelchair wheel with diameter 66 cm.
Calculate the circumference a tire with radius 37 cm.
Calculate the circumference a hula-hoop with diameter 60 cm.
Suppose the circumference of a circular pond is 76.6 m. What is its diameter?
Find the radius of a circle with a circumference of 256 cm.
Find the radius of a circle with a circumference of 113 cm.
An auger is used to drill a hole in the ice, for ice fishing. The diameter of the hole is 25 cm. What is the circumference of the hole?