2025 CGS PRELIMS P1 Q2

In the quadrilateral \(ABCD\), \(BC=5.25\text{ cm}\), \(AC=4.32\text{ cm}\). Angle \(ADC=90^\circ\). Angle \(ACD=35^\circ\).

1. Calculate \(AD\).[1]
2. Given that the area of triangle \(ABC=3.18\text{ cm}^2\), find the obtuse angle \(ACB\).[2]