Radius and Diameter of a Circle
The radius of a circle is the length between a circle's centre and edge.
The diameter of a circle is its radius doubled.
Solving the Question
The given diagram tells us the radius is 4.2 cm.
To solve for the diameter, multiply the given radius by 2:
4.2 × 2 = 8.4
Therefore, the diameter of the circle is 8.4 cm.
Answer
Radius: 4.2 cm
Diameter: 8.4 cm