Part 1)
we know that
the property of cyclic quadrilaterals for which opposite angles are supplementary
then
m∠A°+43°=180°------------> m∠A=180°-43°=137°
the answer is m∠A=137°
Part 2) Quadrilateral ABCD is inscribed in a circle. What is the measure of angle A?
we know that
the property of cyclic quadrilaterals for which opposite angles are supplementary
then:
m∠A+m∠C=180∘
(2x+9)+(3x+1)=180---------------> 5x+10=180
x=(180-10)/5=34
m∠A=2x+9-------------> 2*34+9=77°
the answer is m∠A=77°