Arectangular swimming pool with length 50 ft and width 30 ft is surrounded by a sidewalk of uniform width. write a polynomial function that describes the area of the sidewalk in terms of its width

Let x represent the width of the sidewalk.
the swimming pool is a rectangle, l=50, w=30
the sidewalk forms a larger rectangle, l=50+2x, width=30+2x 
to find the area of the sidewalk, you can subtract the area of larger rectangle from the smaller rectange:
(50+2x)(30+2x)-(50*30)=4x²+160x

Another to do it is the cut sidewalk into 4 portions by extending the vertical sides of the pool to the outer edge of the sidewalk.
the two rectangle on the left and right each has area of (30+2x)*x=2x²+30x
the two horizontal rectangle each has an area: 50x
add them up: 2x²+30x+2x²+30x+50x+50x=4x²+160x

Answer: d. 39 cmin the diagram, the approximate length of the minor arc de is 39 centimetres.step-by-step explanation: the formula for the length of an arc in a circle is as displayed below.let the length of the minor arc de = xx = 2( pi )r × angle of sector / 360°from this, we will substitute the values given from the problem into the formula to obtain the length of the minor arc de.x = 2( pi )r × angle of sector / 360°r = radius = 25cmpi as an approximate value = 3.14angle of sector = 120°x = 2( 3.14 )( 25 ) × 120° / 360°x = 157 × 1 / 4x = 39.25x = 39 ( rounded to the nearest whole number as an approximate value )