Answer:
Explanation:
Use SAS congruency; AD=DC, and they both share side BD. Also, BD is the perpendicular bisector to AC, so it also forms 2 right angles. Proof using SAS.
Or, if you don’t know SAS congruency, you may use SSS congruency;
Use the Pythagorean theorem. Side length AB^2 = AD^2 + BD^2
BC^2 = DC^2 + BD^2.
AD=DC, so therefore AB = BC. Use SSS congruency, and there you go.