If \( A D=13 \) units and \( D C=5 \) unis, calculate the length of ED.

To calculate the length of \( ED \), we need to determine the relationship between the points \( A, D, C, \) and \( E \). However, based on the information provided (i.e., \( AD = 13 \) units and \( DC = 5 \) units), it's unclear how \( E \) is connected to these points. Assuming \( E \) lies on the line segment \( AC \), we can first find the length of \( AC \) by adding \( AD \) and \( DC \): \[ AC = AD + DC = 13 + 5 = 18 \text{ units.} \] Without additional context regarding point \( E \)'s position along \( AC \) or any other geometric properties, we cannot definitively calculate the length of \( ED \). If \( E \) was meant to be at any specific location relative to \( D \) or the segment \( AC \), further details are needed to solve for \( ED \). Could you provide more information about where \( E \) is located?