Answer:
[tex]y = 23[/tex].
Step-by-step explanation:
Two right triangles are congruent by the [tex]\texttt{HL}[/tex] postulate if and only if:
In this example, the hypotenuses of the two right triangle are [tex]\textsf{CO}[/tex] and [tex]\textsf{FD}[/tex], respectively.
For these two right triangles to be congruent by [tex]\texttt{HL}[/tex], these two lengths should be equal to one another. Equate these two lengths and solve for [tex]y[/tex]:
[tex]\textsf{CO} = \textsf{FD}[/tex].
[tex]73 = (3\, y + 4)[/tex].
[tex]y =23[/tex].