Children with expressive language disorder have difficulty conveying or expressing information in speech, writing, sign language or gesture. (For preschool children, the difficulty expressing themselves in writing is not evident, as they have not started formal education.)
A rectangle is defined as a parallelogram (a quadrilateral with two sets of parallel sides) with the non-parallel sides joining perpendicularly (at 90Â°). A square is a rectangle with the additional constraint the all four sides be of equal length.
Opposite sides of a rectangle are equal in length, and the interior angles are all 90Â° in measure; thus, we can draw the rectangle as shown below. One characteristic of rectangles that we can readily calculate is its perimeter, which is the sum of the lengths of all the sides.