### Video Transcript

Identify all the radii in the following circle.

The word radii is just a plural of the word radius. So weโre being asked to find all of the lines in the diagram, which are a radius of the given circle. Recall that the radius of a circle is any line which joins the center of the circle to a point on the circumference. The center of the circle weโve been given is the point ๐. So any line which connects ๐ to the circumference will be a radius of this circle.

First, we note that the line segment ๐๐ต is a radius of the circle as ๐ is the center and ๐ต is a point on the circumference. The line segment ๐๐ถ is also a radius of the circle, as is the line segment ๐๐ธ. Finally, we note that the line segment ๐๐น is also a radius of this circle. So weโve identified four line segments which are radii of this circle, ๐๐ต, ๐๐ถ, ๐๐ธ, and ๐๐น.

Letโs just have a brief look at what some of the other line segments in this circle are called. The line segments ๐ต๐ธ and ๐น๐ถ are diameters of the circle because they each join two points on the circumference of the circle and pass through the circleโs center. The line segment ๐น๐ท is a chord of the circle because it joins two points on the circumference but doesnโt pass through the center of the circle.

We need to be aware of the different types of lines that exist within circles. These lines are radii, diameters, and chords, all of which weโve seen examples of in this question.