Answer:
(Statement ------> Reason)
1 ) Circle C is constructed so that CD = DE = AD; Line segment CA is a radius of circle C. -------> Given
2) Line segment CD is congruent to line segment DE; line segment DE is congruent to line segment AD --------> Definition of congruence
3) Triangle ACD is an isosceles triangle; Triangle ADE is an isosceles triangle. --------> Isosceles triangle theorem
4) m<CAD + m<DCA + m<ADC = 180 degrees; m<DAE = m<AED + m<EDA = 180 degrees ---------> Substitution property
5) CD = DE --------> Isosceles triangle theorem
6) m<CAD = m<DCA; m<CAE = m<AED --------> Definition of congruence
7) m<CAD + m<CAD + m<ADC = 180 degrees; m<DAE = m<DAE + m<EDA = 180 degrees -------> Substitution property
8) 2(m<CAD) + m<ADC = 180 degrees; 2(m<DAE) + m<EDA = 180 degrees --------> Addition
9) m<ADC = 180 degrees - 2(m<CAD); m<EDA = 180 degrees - 2(m<DAE) -------> Addition subtraction property
10) Angle ADC and Angle EDA are a linear pair. ----------> Linear pair postulate
11) Angle ADC + Angle EDA ---------> Linear pair postulate
12) m<ADC + m<EDA = 180 degrees -------> Definition of supplementary angles
13) 180 degrees - 2(m<CAD) + 180 degrees - 2(m<DAE) = 180 degrees -------> Substitution property
14) 360 degrees - 2(m<CAD) - 2(m<DAE) = 180 degrees -------> Addition
15) -2(m<CAD) - 2(m<DAE) = -180 degrees -----------> Subtraction property
16) m<CAD + m<DAE = 90 degrees ----------> Definition of complementary angles
17) m<CAD + m<DAE = m<CAE -----------> Angle addition postulate
18) m<CAD + m<DAE = m<CAE = 90 degrees ------> Substitution property
19) Angle CAE is a right angle ------> Definition of right angle
20) m<CAE = 90 degrees -------> Definition of perpendicular
21) Line segment AE is tangent to circle C. -------> AE ⊥ AC
Step-by-step explanation:
I'm not sure if the reason for #9 is correct, but that's what someone else in a different answer said, so I went ahead and put it.