The interior angle of a circle is equal to 180 degrees. Let me sketch a "proof" for this non-intuitive result. For the purpose of simplicity and without loss of generality, let assume that a n-side polygon is regular.
Now, we can calculate the sum of the interior angles in the n-side polygon as:
(n-2)*180o (1)
where n represents the number of sides.
N order to find an interior angle in the n-side polygon we simply divide the formula (1) by n in order to get an interior angle, so:
[(n-2)*180]/n=
=(180n-360)/n
=(180n)/n-360/n
=180-360/n (2)
Now, it is easy to see that as the number of the side of the polygon increase, i.e. form a pentagon to a hexagon, the polygon becomes to look more and more like a circle. If we use equation (2) we can see that as n increases the first term stays the same 180, but the 360/n will become smaller and smaller. Now, let me imagine a is very big number "infinitely" big number then the last term will disappear and one can rewrite (2) as
180-360/n= (n becomes "infinitely big")=180.
That is the line of reasoning why the answer is 180.
Chat with our AI personalities
inscribed angle
This is the definition of an inscribed angle in geometry. An inscribed angle is formed by two chords in a circle that also share a common point called the vertex.
The interior angle of an n-sided polygon total 90(2n - 4) degrees
900 degrees
There is no specific limitation on any one angle of an inscribed quadrilateral.