7 Theorems

Hello Fellow ClassMates,


The day started out with Mr. Maksymchuk giving us an introduction to circle geometry, we watched him construct the 7 theorems on Euklid. Neat Stuff I tell ya!



Here is a look at Theorem 1

If an angle (inscribed) in a circle intercepts a semi circle (or semi-circular arc), then the angle inscribed is a right angle.

Theorem 2

If two angles inscribed in the same circle intercept the same arc, then the angles are congruent.

Theorem 3

If an inscribed angle and a a central angle in the same circle intercept the same arc, then the measure of the central angle must be twice the measure of the inscribed angle.


Theorem 4

If in a circle, a radius or diameter intersects a chord at a right angle, then chord is bisected at the point of intersection.

Theorem 5

If a line is tangent to a circle, then the tangent line is perpendicular to the radius/diameter at the point of tangency.

Theorem 6

If tangent lines to the same circle intersect at a common external point, then the segments created from the circle to the common external point are congruent.

Theorem 7

If a quadrilateral is cyclic, then opposite angles in the quadrilateral are supplementary (have a sum of 180).

Those are the 7 Theorems we were told to know, I hope this post is helpful to everyone. Thankyou for your time.

Captain Kolan