Answer:
400 ft²
Step-by-step explanation:
The maximum area of a rectangle results from it being a square. The rectangle (or square) must have 4 equal sides in order to maximize area. But in this case, one side is a wall. That means that the remaining three sides will be = 60 / 3 = 20 feet long. You formed an square that is 20 ft x 20 ft = 400 ft²
So, 4 x 3 is 12, so 4 blades cost 79.74 x 3 (because every turbine has 3 blades each) is 318.96
16, first you need to add on the four he lost to the 18 he ended with.
Answer
According to newton law of cooling

and

now At Ta = 100
T₀ = 10 °C
T₁ = 12° C

10 = C + 100
C = -90
now,



at time equal to t
T(t) = 70



t = 48.88 s
hence, after 48.88 s the temperature of the body will be 70°C
b) time taken to reach 98°C



t = 390 s
hence, after 390 s the temperature of the body will be 98°C