Answer:
[tex]142km^{2}[/tex]
Step-by-step explanation:
you need to find the area of every side and then add them all together so
you do the equation
[tex]2[(7*5)+(3*5) + (7*3)][/tex]
I multiply everything by 2 because there is 2 of every side
once you solve this you get the answer of [tex]142km^{2}[/tex]