Determine the angle at the center of a circle with radius 8.0cm for an arc length of 12.0cm

What can be said about the relationship between triangles and circles? check all that apply. a) many circles can be inscribed in a given triangle b) exactly one triangle can be inscribed in a given circle c) exactly one circle can be inscribed in a given triangle d) many triangular shapes can be circumscribed about a given circle

What statement is true? 2x^2-9x+2=-1

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?