Noah is baking a two-layer cake, in which the bottom layer is a circle and the top layer is a triangle. If segment AB = 5 inches and arc AB≅ arc AC, what does Noah know about the top layer of his cake? Circumscribed circle D around triangle ABC, arcs AB and AC are congruent. segment AB is twice the length of segment BC because their arcs are congruent; therefore, ΔABC is an isosceles triangle. segment AB is twice the length of segment BC because their arcs are congruent; therefore, ΔABC is an equilateral triangle. segment AB ≅ segment BC because their arcs are congruent; therefore, ΔABC is an isosceles triangle. segment AB ≅ segment BC because their arcs are congruent; therefore, ΔABC is an equilateral triangle.