see attachment
each pannel is x wide
3 of them
and 2 spaces of 4.25 between
they add to 50.5
therefor
3x+2(4.25)=50.5
3x+8.5=50.5
minus 8.5 both sides
3x=42
divide both sides by 3
x=14
each pannel is 14 wide
they are paralellograms
the area of a paralellogram is legnth of base times height (it works for all paralellograms)
for this one, we can rorate the thing 90 degrees and say the base is 20.5 in and the height is 14
area=20.5 times 14
area=287
area of 1 pannel=287 square inches