Tags » If And Only If

Ceva and Menelaus

Here is a result I worked out using the theorems of Ceva and Menelaus.
The points P, Q and R lie on the sides BC, CA and AB of triangle ABC respectively (not necessarily in their interiors), such that they are not collinear. 263 more words


60 degrees special property

The triangle ABC has circumcentre O, incentre I and orthocentre H.
A, O, I, H and C are concyclic if and only if ∠ABC = 60°. 338 more words


More cyclic quadrilaterals

Just to pass the time, a very simple result (again found by playing on Geogebra):

A triangle ABC is acute-angled. The point P is located in the interior of ABC. 286 more words


Propositional Logic: Building Propositions

Previously, we focused on basic propositions and how they play a part in arguments. But in addition to the rather straightforward types of propositions we saw, we can also use… 754 more words

Critical Thinking

Three circles and one egg

Two circles, X and Y, intersect at two points A and B. One line is drawn through X, cutting it at two points, P and Q; another line, not parallel to the first, is drawn through Y, cutting it at two points, R and S. 350 more words


"Nervosa" in If and Only If, Issue Two!

As I mentioned a couple posts ago, I had a short poem published in the new issue of If and Only If: A Journal of Body Image and Eating Disorders… 15 more words