Answer:
4 right angles
Step-by-step explanation:
All rectangles have 4 right angles in common.
All the rectangles have all their right angles (there are four of them) in common. The bottom-left box correctly states the commanality.
A rectangle consists of 4 sides, connected end to end, such that all the adjacent sides are at right angles (90°) with each other.
Due to four corners in a rectangle, and all corners internally having right angles, so all the rectangles have 4 right angles in common.
It isn't necessary for all the four sides being equal (its for square though, a special case of rectangles). (we assume that the fourth box is stating that all 4 sides of all rectangles are same in length)
But all the rectangles have their oppositely faced side pairs having equal length within their pairs.
Also, even if all the rectangles have 4 sides, but one rectangle can have some other lengthed sides, and another rectangle can have its sides of other lengths.
Thus, all the rectangles have all their right angles (there are four of them) in common (well right angle is not the only thing they've got in common, like they've got exterior angles common, 4 vertices etc). The bottom-left box correctly states the commanality.
Learn more about rectangles here:
https://brainly.com/question/1365755
