What does open and closed circles mean on a graph of a piecewise function? Pls help me out don’t get it

An open circle at the end of an interval means that the end point is not included in the interval, i.e. strictly less than or strictly greater than. A closed circle means the end point is included (equal to).

Open circles are used for numbers that are less than or greater than (< or >). Closed circles are used for numbers that are less than or equal to and greater than or equal to (≤ or ≥).

Step-by-step explanation:

An open circle at the end of an interval means that the end point is not included in the interval, i.e. strictly less than or strictly greater than. A closed circle means the end point is included (equal to).

Step-by-step explanation: Mark Me Brainliest.

i'm assuming it's looking for the missing length, which should be 4cm

hope this !