Uncle Li's average step length is about 70cm. He walked around the edge of a rectangle which is twice the length and width. He just walked 900 steps?

Uncle Li's average step length is about 70cm. He walked around the edge of a rectangle which is twice the length and width. He just walked 900 steps?

70cmx900=63000cm
Let the width of the rectangle be x, then the length is 2x
x+x+2x+2x=63000
x=1500cm
So the length of the rectangle is 1500x2 = 3000cm
1500x3000 = 450000 (cm2)