The answer is (-2, -1) hope this helps!
As I've shown on picture that I attached:
∠ADC=∠ADB+∠BDC⇒134=5x+4+7x-2
12x+2=134
12x=132⇒x=132/12
x=11
Angle BDC measure 7x-2=7*11-2⇒∠BDC=75.
Area of a circle: πr²
Data:
diameter: 21 cm
radius=diameter/2=21 cm/2=10.5 cm
area of this circle: π(10.5 cm)²=110.25π cm² (≈346.36 cm²)
Answer: area=110.25π cm²