A rectangle is divided into 9 small rectangles if by parallel lines to its sides, as shown in the figure.
https://cdn.artofproblemsolving.com/attachments/e/d/1fd545862a3c7950249ec54a631c74e59fb9ed.png
The four numbers written indicate the areas of the four corresponding rectangles.
Prove that the total area of the rectangle is greater than or equal to 90. geometryareasRectanglesrectangle