sheep(noun) woolly usually horned ruminant mammal related to the goat. sheep(noun) a timid defenseless simpleton who is readily preyed upon. sheep(noun) a docile and vulnerable person who would rather follow than make an independent decision.
The incenter is the one point in the triangle whose distances to the sides are equal. (See picture) 1  If the triangle is obtuse, such as the one on pictured below on the left, then the incenter is located in the triangle's interior.  If the triangle is acute, then the incenter is also located in the triangle's interior.
By Euler's theorem in geometry on the distance between the circumcenter and incenter of a triangle, two concentric circles (with that distance being zero) are the circumcircle and incircle of a triangle if and only if the radius of one is twice the radius of the other, in which case the triangle is equilateral.