I don’t know how to solve this. Can someone help please?

Step-by-step explanation:
[tex]In\: \triangle ABC \:\&\: \triangle ADC\\\\
\angle BAC\cong \angle DAC... (given) \\\\
AC \cong AC....(common) \\\\
\angle ACB\cong \angle ACD... (each\: 90°)\\\\
\therefore \triangle ABC \cong \triangle ADC.. (By\:ASA) [/tex]