A rectangle is a planar quadrilateral with all its angles being right angles. A special case of a rectangle is a square.
The opposite sides of a rectangle are parallel.
$$C=2 \times (a+b)$$
where,
a,b— sides of the rectangle.
$$S=a\times b$$
The diagonal of a rectangle can be found using the Pythagorean theorem.
$$d=\sqrt{a^{2}+b^{2}}$$