Relation between diameter and circumference

The difference of the circumference of a circle and its radius is 74 cm. Determine its diameter and circumference.

The relation between the circumference of an electron orbit in a hydrogen atom and the de broglie wavelength of the electron in the same orbit is given by

The ratio between the diameters of two cirlces is 3:5. Find the ratio between their : (i) radii (ii) circumferences (iii) areas.

If the difference between the circumference and diameter of a circle is 30 cm, then what is the radius of the circle ?

The difference between the circumference and the diameter of the circle is 15 m . What is the area of the circle ?

The differences between the circumference and diameter of a circle is 60 cm, then radius is

If the difference between the circumference and diameter of a circle is 30 cm, then the radius of the circle must be