we are given
Point A lies on the circumference of the unit circle
so, we can write equation of circle as
![x^2 +y^2 =1^2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/heovqe59t3j201e1z3erhcdawua1oto8un.png)
now, we are given
![x =0.12](https://img.qammunity.org/2019/formulas/mathematics/middle-school/8bftkr056u3n2g5pr60rszgp403uw1djur.png)
so, we can plug it in equation and find y
![0.12^2 +y^2 =1^2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/88i221rtsz4bfskhyopr3iuvfe324qpixn.png)
![y^2=0.9856](https://img.qammunity.org/2019/formulas/mathematics/middle-school/6nx18n2k5zsvprfyiqz8yz9llz80zr2bhn.png)
![y=√(0.9856),\:y=-√(0.9856)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/95ueslzv5z3qfn7h6k8zf77hwksezl5oze.png)
Since, point-A lies in first quadrant
so, both x-value and y-value will be positive
so, we get
.............Answer