Answer: Second option, it is not a rectangle because the sides don't meet at right angles.
Step-by-step explanation:
A rectangle is a shape with 4 sides, such that we have two pairs of parallel sides, where the length of the parallel sides is equal.
so we have two parallel sides with length L and two parallel sides with length L'.
In this figure ,we can see two sides with length 20 and other two with length 21, and this is a rectangle only if the sides meet at 90°degree angles (this would mean that the opposite sides are parallel)
to see this, we can think that the triangle formed by the diagonal and two sides is a triangle rectangle, then using the Pythagorean theorem we should have that:
20^2 + 21^2 = 28^2
841 = 784
So this is not a triangle rectangle, meaning that the angle between the side of 20 and the side of 21 is not a right triangle, then the figure is not a rectangle.
The correct option is the second one.
