Answer:
Step-by-step explanation:
[tex]A=\dfrac{bh}{2}\\\\A=117\ cm^2\\b=13\ cm[/tex]
Substitute:
[tex]117=\dfrac{13h}{2}[/tex] multiply both sides by 2
[tex]234=13h[/tex] divide both sides by 13
[tex]18=h\to h=18\ cm[/tex]
