A square has an area of $25.$ A rectangle has the same width as the square. The length of the rectangle is double its width. What is the area of the rectangle?
I need to find the area of the rectangle, which is the product of its length and width. I know the width of the rectangle is the same as the side of the square, so I can use the area of the square to find the width. The area of a square is the square of its side, so if the area is $25,$ then the side is $\sqrt{25} = 5.$ Therefore, the width of the rectangle is also $5.$ The length of the rectangle is double its width, so the length is $2 \times 5 = 10.$ Now I have the length and width of the rectangle, so I can multiply them to get the area. The area of the rectangle is $10 \times 5 = 50.$ 