Before talking around the quadrilaterals angle sum property, let us recall what angles and quadrilateral is. The edge is created when 2 line segment joins at a single point. An angle is measure up in levels (°). Square angles space the angles developed inside the shape of a quadrilateral. The square is four-sided polygon which deserve to have or not have actually equal sides. It is a closed number in two-dimension and also has non-curved sides. A quadrilateral is a polygon which has 4 vertices and 4 political parties enclosing 4 angles and the amount of every the angle is 360°. When we draw a draw the diagonals come the quadrilateral, it develops two triangles. Both these triangles have an angle amount of 180°. Therefore, the total angle sum the the quadrilateral is 360°. Angle sum is among the nature of quadrilaterals. In this article, w will discover the rule of angle sum property.

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QuadrilateralArea of Quadrilateral
Construction the QuadrilateralsTypes that Quadrilaterals

Angle Sum residential or commercial property of a Quadrilateral

According come the angle sum building of a Quadrilateral, the sum of all the four interior angle is 360 degrees.

Proof: In the square ABCD,

∠ABC, ∠BCD, ∠CDA, and ∠DAB are the internal angles.AC is a diagonalAC divides the quadrilateral into two triangles, ∆ABC and ∆ADC

We have actually learned that the amount of interior angles of a quadrilateral is 360°, that is, ∠ABC + ∠BCD + ∠CDA + ∠DAB = 360°.

let’s prove the the sum of every the four angles of a square is 360 degrees.

We know that the sum of angle in a triangle is 180°.Now take into consideration triangle ADC,

∠D + ∠DAC + ∠DCA = 180° (Sum of angles in a triangle)

Now think about triangle ABC,

∠B + ∠BAC + ∠BCA = 180° (Sum of angle in a triangle)

On including both the equations obtained over we have,

(∠D + ∠DAC + ∠DCA) + (∠B + ∠BAC + ∠BCA) = 180° + 180°

∠D + (∠DAC + ∠BAC) + (∠BCA + ∠DCA) + ∠B = 360°

We view that (∠DAC + ∠BAC) = ∠DAB and (∠BCA + ∠DCA) = ∠BCD.Replacing them us have,

∠D + ∠DAB + ∠BCD + ∠B = 360°

That is,

∠D + ∠A + ∠C + ∠B = 360°.

Or, the amount of angle of a square is 360°. This is the angle sum residential property of quadrilaterals.

Quadrilateral Angles

A quadrilateral has actually 4 angles. The amount of its inner angles is 360 degrees. We can discover the angles of a quadrilateral if we know 3 angles or 2 angles or 1 angle and also 4 lengths the the quadrilateral. In the image offered below, a Trapezoid (also a form of Quadrilateral) is shown.

The sum of every the angles ∠A +∠B + ∠C + ∠D = 360°


In the instance of square and rectangle, the value of all the angles is 90 degrees. Hence,

∠A = ∠B = ∠C = ∠D = 90°

A quadrilateral, in general, has sides of different lengths and also angles of various measures. However, squares, rectangles, etc. Room special species of square with some of their sides and also angles being equal.

Do the Opposite side in a Quadrilateral amounts to 180 Degrees?

There is no relationship in between the the contrary side and the angle actions of a quadrilateral. To prove this, the scalene trapezium has the side size of various measure, which walk not have actually opposite angles of 180 degrees. Yet in situation of part cyclic quadrilateral, such as square, isosceles trapezium, rectangle, opposing angles room supplementary angles. It method that the angles include up come 180 degrees. One pair the opposite square angles are equal in the kite and also two pair of opposing angles are equal in the quadrilateral such together rhombus and also parallelogram. It method that the sum of the quadrilateral angle is same to 360 degrees, yet it is not crucial that the opposite angles in the quadrilateral have to be the 180 degrees.

Types the Quadrilaterals

There space basically five types of quadrilaterals. They are;

Parallelogram: Which has opposite sides as equal and parallel to each other.Rectangle: Which has actually equal the contrary sides but all the angles space at 90 degrees.Square: Which all its 4 sides as equal and angles in ~ 90 degrees.Rhombus: its a parallelogram through all the sides together equal and its diagonals bisects each various other at 90 degrees.Trapezium: Which has actually only one pair the sides as parallel and the sides might not be same to each other.


1. Discover the fourth angle of a square whose angles space 90°, 45° and also 60°.

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Solution: by the angle sum home we know;

Sum of all the internal angles of a quadrilateral = 360°

Let the unknown angle be x


90° + 45° + 60° + x = 360°

195° + x = 360°

x = 360° – 195°

x = 165°

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