WT60: Acute and obtuse triangles
We define acute and obtuse triangles, and give inequalities for acuteness in terms of the spreads of the triangle. Then we look at the circumcenter of the triangle, and express it as an affine combination of the vertices. The Triangle spread rules play a role. This video is part of the WildTrig series, which introduces Rational Trigonometry and applies it to many different aspects of geometry.