Answer:
15 cm²
Step-by-step explanation:
To find the volume of a prism you multiply the area of the end face (pentagon in this example) by the length (9 cm). Here you would reverse that and divide the volume by the length to find the area. 135/9 is 15 so the area of the pentagon is 15 cm².
In equation form would be:
V=A×L [V=volume A=area L=length]
So if you do inverse operations you would divide the volume by the length to get the area.
V/L=A
