Answer:
The width is 20 ft and the length is 80 ft
Explanation:
Area = l * w
l = w +60
SA = 1600 ft^2 ( which is the regular area) The surface area of the water is just what is on top which is length times width
1600 = l*w
Substitute in l = w+60
1600 = (w+60) *w
Distribute the w
1600 = w^2 +60w
Subtract 1600 from each side
1600-1600 = w^2 + 60w -1600
0 = w^2 + 60w -1600
Factor
0=(w-20) (w+80)
Using the zero product property
w-20=0 w+80 =0
w=20 or w=-80
The width cannot be negative so
w=20
Now we need to find the length
l = w+60
l = 60+20
l =80