### Video Transcript

Is the diameter the longest chord
in a circle?

Remember, a chord is a line that
joins one point on the circumference of a circle to another. So, if we take a circle whose
center is 𝑜, we could have a chord here, one here, or one here. There are an infinite number of
chords that we can draw. Note that to create the longest
chord, that’s the longest line by joining two points on the circumference, we’re
going to need to find the widest part of the circle.

Now, this line must pass through
the center of the circle. But of course, we know that the
diameter is the line that passes through the center of the circle and joins two
points on its circumference. And this means that we can say that
yes, the diameter is the longest chord in a circle.