Also, the opposite angles of square sum up to 180 degrees.For a parallelogram to be cyclic or inscribed in a circle, the opposite angles of that parallelogram should be supplementary. TERMINAL EXERCISES 1. Join these points to form a quadrilateral. Then,Therefore, an inscribed quadrilateral also meet the according to which, the sum of all the angles equals 360 degrees. Any two of these cyclic quadrilaterals have one diagonal length in common.This was derived by the Indian mathematician Vatasseri If the diagonals of a cyclic quadrilateral intersect at Quadrilateral whose vertices can all fall on a single circle The second shape is not a cyclic quadrilateral. A square PQRS is inscribed in a circle with centre O. zIf a pair of opposite angles of a quadrilateral is supplementary, then the quadrilateral is cyclic. Hence, not all the parallelogram is a cyclic quadrilateral.A cyclic quadrilateral is a quadrilateral which has all its four vertices lying on a circle. Every corner of the quadrilateral must touch the circumference of the circle. Take a circle and choose any 4 points on the circumference of the circle. This is one of the theorems known as the Japanese theorem. The orthocenters of the same four triangles are the vertices of a quadrilateral congruent to ABCD, and the centroids in those four triangles are vertices of another cyclic quadrilateral. Hence,The circumradius of cyclic quadrilateral is expressed in terms of the two diagonals and distance between the midpoints of the diagonals.Let p and q are the diagonals of cyclic quadrilateral and x is the distance between the midpoints of diagonals p and q. A quadrilateral is a 4 sided polygon bounded by 4 finite line segments. It means that all the four vertices of quadrilateral lie in the circumference of the circle. To our surprise, the sum of the angles formed at the vertices is always 360In a cyclic quadrilateral, the sum of either pair of opposite angles is supplementary.Given: A cyclic quadrilateral ABCD inscribed in a circle with center O.The converse of this theorem is also true which states that if opposite angles of a quadrilateral are supplementary then the quadrilateral is cyclic.The quadrilateral whose vertices lies on the circumference of a circle is a cyclic quadrilateral. zSum of the opposite angles of a cyclic quadrilateral is 180°. The direct theorem was Proposition 22 in Book 3 of Another necessary and sufficient conditions for a convex quadrilateral Four unequal lengths, each less than the sum of the other three, are the sides of each of three non-congruent cyclic quadrilaterals,The area of a cyclic quadrilateral with successive sides where there is equality if and only if the quadrilateral is a square. Property 2: The exterior angle of a cyclic quadrilateral is equal to the interior opposite angle. In a cyclic quadrilateral with successive vertices For the sum of the diagonals we have the inequalityIn any convex quadrilateral, the two diagonals together partition the quadrilateral into four triangles; in a cyclic quadrilateral, opposite pairs of these four triangles are A set of sides that can form a cyclic quadrilateral can be arranged in any of three distinct sequences each of which can form a cyclic quadrilateral of the same area in the same circumcircle (the areas being the same according to Brahmagupta's area formula). A cyclic quadrilateral is a quadrilateral drawn inside a circle. Then the radius of this quadrilateral will be:Suppose a,b,c and d are the sides of a cyclic quadrilateral and p & q are the diagonals, then we can find the diagonals of it using the below given formulas:\(p=\sqrt{\frac{(a c+b d)(a d+b c)}{a b+c d}} \text { and } q=\sqrt{\frac{(a c+b d)(a b+c d)}{a d+b c}}\)If a,b,c and d are the sides of a inscribed quadrialteral, then its area is given by:There is two important theorems which prove the cyclic quadrilateral.The ratio between the diagonals and the sides can be defined and is known as Cyclic quadrilateral theorem. Let ∠A, ∠B, ∠C and ∠D are the four angles of an inscribed quadrilateral. In a cyclic quadrilateral, the sum of a pair of opposite angles is 180 0 (supplementary) If the sum of two opposite angles are supplementary then it’s a cyclic quadrilateral; The area of a cyclic quadrilateral is [s(s-a)(s-b)(s-c)(s-c)] 0.5 where a, b, c, and d are the four sides of the quadrilateral and the perimeter is 2s

A cyclic quadrilateral is a quadrilateral that can be inscribed in a circle, meaning that there exists a circle that passes through all four vertices of the quadrilateral.