Given data:
The first given side is FG=21.
The second given side is GH=12.
The expression for the Pythagoras theorem is,
![(FG)^2+(GH)^2=(FH)^2](https://img.qammunity.org/2023/formulas/mathematics/college/2kwbtkkwgha64im5maivuvyx5q7ummee79.png)
Substitute the given values in the above expression.
![\begin{gathered} (21)^2+(12)^2=(FH)^2 \\ 585=(FH)^2 \\ FH=24.18 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/dd3vnslfopgfax8wr3qtvtyggd5k0klcmv.png)
The expression for the angle F is,
![\begin{gathered} \tan (m\angle F)=(GH)/(GF) \\ =(12)/(21) \\ m\angle F=29.74^(\circ) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/8wpjvaaeud759bmw0gwa0a612rl5eizbg8.png)
The angle H is,
![\begin{gathered} m\angle H+m\angle G+m\angle F=180\circ \\ m\angle H+90^(\circ)+29.74^(\circ)=180^(\circ) \\ m\angle H=60.26^(\circ) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/2yms2omrpg7pgxrcakhbyxlce2x1awtvd5.png)
Thus, the FH length is 24.18, m∠F=29.74 degrees, and m∠H is 60.26 degrees.