Properties of Rectangles

Before this, knowSymmetries of Rectangles

Interactive · 3 questions

Rectangles are parallelograms with right angles. This means that all their angles are 90 degrees, their diagonals bisect, and their two pairs of sides are parallel.

Area and Perimeter

The perimeter of a rectangle is P=2w+2lP=2w + 2l

The area of a rectangle is A=lwA = lw where l is the length and w is the width.

Symmetry

Rectangles have two lines of symmetry. They are:

Special Properties about Rectangles

A rectangle is a cyclic quadrilateral - that is, every one of its points would fit on the edge of a circle. The radius of that circle would be half of a diagonal.

The diagonals are of equal length and bisect at equal angles.

Here's a little quiz about rectangles: (don't look at the article you just read)

If a diagonal of a rectangle is 13 inches and one of its sides is 12, what is the rectangle's perimeter?

Choose one answer

Spot the idea in disguise

In a contest problem, this idea hides inside a situation you have not seen before. Learning to spot it is the real skill. These are real problems from the AMC 8, AMC 10, AMC 12 and AIME, the national math competitions for middle and high school students, each with a worked solution on LIVE by Po-Shen Loh.

Type a concept, like “slope” or “photosynthesis”.

↑ ↓ to choose · Enter to openSearch explanations and problems