find angle BAD of the diagram.

[tex]∠BAD≈65.22°[/tex]
Note:
The following formula is tan formula:
[tex]tan(\theta)=\dfrac{opposite}{adjacent}[/tex]
1) Finding the tan of ∠BAC
[tex]tan(\theta)=\dfrac{4}{5}[/tex]
[tex]\theta=tan^-1(\dfrac{4}{5})[/tex]
2) Finding the tan of ∠CAD
[tex]tan(\theta)=\dfrac{3}{6}[/tex]
[tex]\theta=tan^-1(\dfrac{3}{6})[/tex]
3) Add the value of ∠BAC to the value of ∠CAD
[tex]tan^-1(\dfrac{4}{5})+tan^-1(\dfrac{3}{6})≈65.22°[/tex]
4) The sum of interior angles in quadrilateral is 360°
Then
[tex]tan(∠BAC)+tan(∠ACB)+tan(∠CAD)+tan(∠ACD)=360°[/tex]
[tex]tan^-1(\dfrac{4}{5})+tan^-1(\dfrac{5}{4})+tan^-1(\dfrac{3}{6})+tan^-1(\dfrac{6}{3})=180°[/tex]
[tex]180°+∠CDA+∠CBA=^?360[/tex]
[tex]180°+90°+90°=^?360°[/tex]
[tex]360°=360°[/tex]