How can i find the length of a chord?

Chord length = 2√r²-d²
r= radius of the circle
d= perpendicular distance from the chord to the circle center.

Example:
radius = 5cm
distance = 4cm

2√5²-4²
=2√25-16
=2√9
=2×3
=6cm

6 cm.

Hope this helped!