This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
The Diameter is the longest chord in a circle which passes through the center of the circle and Radius is the distance from the center to the any point on the circle's circumference which is equal to half the length  of the diameter.
1 5 1
Radius - A line segment starting from on point of the circumference to the center of the circle is called radius. It is half the length of diameter. 

Diameter is the longest chord of a circle that passes through its center.