Simplify this power raised to a power: (54)4

The function models the number of accidents per 50 million miles driven as a function

The area of a rectangle is 10 cm^2. one side of the rectangle is x cm. express the perimeter of the rectangle in terms of x and show that this rectangle cannot have a perimeter of 12 cm. the perimeter of the rectangle in terms of x is __ cm

What is the simplified form of square root of 400 to the 100th power ?