# Definition of Square | Formula of Square

Square We are start today online tutoring about Square. Our Tutor always try to do best for our learner. Today in eteacherg.com we study about Square. This chapter content Square definition, Features of Square and Formula of Square, area of square formula. In previous chapter we had read about Rectangle. We read today in Tutor Dose about Square definition and Formula of Square. Square is a 2D geometric shape, which has sides. This is also very important chapter for point of view of examination. So read this lesson carefully.

# Square

## Definition of Square

“Simple plane shape surrounding by four equal sides, which at least one angle is right angle, called Square.”

## Features of Square

• There are four sides in a square.
AB, BC, CD and DA
• All four sides are equal.
AB = BC = CD = DA
• Opposite are parallel in Square.
AB ।। CD
• A square have four vertex
A, B, C and D
• Square have four angles.
∠A or ∠DAB
∠B or ∠ABC
∠C or ∠BCD
∠D or ∠CDA
• All four angles are right angle.
∠A ∠B = ∠C = ∠D = 90°
or
∠DAB = ∠ABC = ∠BCD = ∠CDA = 90°
• The sum of all four interior angles are 360 degree.
∠A ∠B + ∠C + ∠D = 360°
or
∠DAB + ∠ABC + ∠BCD + ∠CDA = 360°
• There are two diagonal in a Square.
AC and BD
• Both diagonal are equal and bisect each other.
AC = BD
and
AO = BO = CO = DO
• Exterior angle sum are also 360 degree in Square.
Important Formula of Square
• #### area of square formula(side)2  or  Side × Side  or a2

Here a = side
(When side given in question and ask for Area of Square.)
• diagonal of square formula
$$\displaystyle {{a}^{2}}$$

Here a = side
(When side is given in question and ask for Diagonal of Square.)
• perimeter of square formula
4a
Here a = side
(When side is given in question and ask for Perimeter of Square)
• Radius of Square Incircle r = $$\displaystyle \frac{a}{2}$$
(When side are given)

•  Radius of Square Circumcircle R = $$\displaystyle \frac{d}{2}$$
(When diagonal are given)

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