Quadrilateral cdef is inscribed in circle a. which statements complete the proof to show that ∠cfe and ∠cde are supplementary?
quadrilateral cdef is inscribed in circle a.
quadrilateral cdef is inscribed in circle a, so m arc cde+ m arc cfe= 360°. ∠cfe and ∠cde are which means that their measures are one half the measure of their intercepted arcs. so, m arc cde= 2 ⋅ m∠cfe and arc cfe= 2 ⋅ m∠cde. using the 2 ⋅ m∠cfe + 2 ⋅ m∠cde = 360°. using the division property of equality, divide both sides of the equation by 2, resulting in m∠cfe + m∠cde = 180°. therefore, ∠cfe and ∠cde are supplementary.
a. inscribed angles; substitution property of equality
b. central angles; substitution property of equality
c. inscribed angles; addition property of equality
d. central angles; addition property of equality