Incircle of the Extouch Triangle = Circumcircle of the Mid-Arc Triangle of the Extouch Triangle.

Nine-Point Circle of the Extouch Triangle = Circumcircle of the Euler Triangle of the Extouch Triangle.

Nine-Point Circle of the Extouch Triangle = Circumcircle of the Feuerbach Triangle of the Extouch Triangle.

Brocard Circle of the Extouch Triangle = Circumcircle of the First Brocard Triangle of the Extouch Triangle.

Brocard Circle of the Extouch Triangle = Circumcircle of the Second Brocard Triangle of the Extouch Triangle.

Orthocentroidal Circle of the Extouch Triangle = Circumcircle of the Fourth Brocard Triangle of the Extouch Triangle.

The Incircle of the Extouch Triangle is concentric to the Bevan Circle of the Yff Central Triangle of the Extouch Triangle.

The Nine-Point Circle of the Extouch Triangle is concentric to the Nine-Point Circle of the Fuhrmann Triangle of the Extouch Triangle.

The Spieker Circle of the Extouch Triangle is concentric to the Radical Circle of the Excircles of the Extouch Triangle.

The Spieker Circle of the Extouch Triangle is concentric to the Bevan Circle of the Euler Triangle of the Extouch Triangle.

The Radical Circle of the Excircles of the Extouch Triangle is concentric to the Spieker Circle of the Extouch Triangle.

The Radical Circle of the Excircles of the Extouch Triangle is concentric to the Bevan Circle of the Euler Triangle of the Extouch Triangle.

The Brocard Circle of the Extouch Triangle is concentric to the Lemoine Circle of the Extouch Triangle.

The Lemoine Circle of the Extouch Triangle is concentric to the Brocard Circle of the Extouch Triangle.

The Lemoine Circle of the Extouch Triangle is concentric to the Circumcircle of the First Brocard Triangle of the Extouch Triangle.

The Lemoine Circle of the Extouch Triangle is concentric to the Circumcircle of the Second Brocard Triangle of the Extouch Triangle.

The Circumcircle of the Extouch Triangle is congruent to the Bevan Circle of the Euler Triangle of the Extouch Triangle.

The Circumcircle of the Extouch Triangle is congruent to the Bevan Circle of the Feuerbach Triangle of the Extouch Triangle.

The Spieker Circle of the Extouch Triangle is congruent to the Incircle of the Euler Triangle of the Extouch Triangle.

The Spieker Circle of the Extouch Triangle is congruent to the Nine-Point Circle of the Mid-Arc Triangle of the Extouch Triangle.