A cyclic quadrilateral is one that has concyclic vertices (its corners all fit on the same circle) and, for a simple cyclic quadrilateral, opposite angles are supplementary.
You draw a circle around a circle.
Its the distance from the center of the circle to the edge of the circle.
The cord of a circle that contains the center of that circle is a diameter of that circle.
it becomes a circle inside another circle
A cyclic quadrilateral is one that has concyclic vertices (its corners all fit on the same circle) and, for a simple cyclic quadrilateral, opposite angles are supplementary.
an iscoceles trapezium is concyclic
First make sure you understand that concyclic simply means the points lie on a common circle. We are not told it is a regular pentagon but we will assume it is. We could create pentagons that are not even convex and would not be concyclic.Let's start with a regular pentagon. You can split it up into 5 congruent triangles with the points meeting at the middle. Any side of one of these triangle is connected from each of the vertices of the pentagon to the center of the pentagon. Since all 5 triangles are congruent, this distance must be the same for each of the vertices. So, we see that each of the vertices is equidistant from a given point. Now if we drew a circle centered at that point with a radius equal to the distance between the point and any vertex, that circle would pass through all 5 vertices. Therefore any four ( really all 5), vertices of a regular pentagon are concyclic.A nice proof would use Ptolemy's theorem. I will place a line to an answers.com page that helps with that.Another solution:The pentagon has to be regular. Otherwise, the question is impossible to prove.Consider a regular polygon ABCDE.Take triangles BCD & ECDBC=ED (sides of a regular polygon are equal)CD=CD (common side)
a circle a circle a circle a circle
You draw a circle around a circle.
Circle, Circle, Circle, Circle, Circle, Circle, R1, L2, L1, Triangle, Circle, Triangle, Get A Tank
Its the distance from the center of the circle to the edge of the circle.
Concentric Circles?
Circle II Circle was created in 2001.
A quarter of a circle is 2/8 of a circle. Add to that an eighth (1/8) of a circle (not eight) and this equals 3/8 of a circle. This equates to 37.5 % of a circle.
The cheat is circle,circle,L1,circle,circle,circle,L1,L2,R1,triangle,circle,triangle
The cord of a circle that contains the center of that circle is a diameter of that circle.