Consider triangle BAC and triangle CAD.
[tex]\begin{gathered} \angle ABC=\angle ADC\text{ (Each angle is right angle)} \\ AC=AC\text{ (Common sides)} \\ BC=DC\text{ (Each side is 15)} \\ \Delta ABC\cong\Delta ADC\text{ (By RHS similarity condition)} \end{gathered}[/tex]So by similar traingle,
[tex]\begin{gathered} \angle BAC=\angle DAC \\ \angle BAC=35^{\circ} \end{gathered}[/tex]Determine the measure of angle BAD.
[tex]\begin{gathered} \angle BAD=\angle BAC+\angle DAC \\ =35+35 \\ =70 \end{gathered}[/tex]Thus option A is correct.
