Answer:
B
Explanation:
The formula for a area of the first semi circle is
![(1)/(2) * \pi {r}^(2)](https://img.qammunity.org/2022/formulas/mathematics/high-school/lhv8wx2bl11d7xh1x1zxny2563a0jmqm67.png)
where r is the radius
Since 4 is the diameter, 2 is the radius
plug it in
![(1)/(2) * \pi {2}^(2)](https://img.qammunity.org/2022/formulas/mathematics/high-school/lfokzive379m46tp2wpyueqdgjuy4jahq3.png)
![(1)/(2) * 4\pi](https://img.qammunity.org/2022/formulas/mathematics/high-school/j3i1yvcyz7b2raofs96z62wf37uh3luiw3.png)
![2\pi](https://img.qammunity.org/2022/formulas/mathematics/college/s8tx2lp4i92tra1th9nd42hubveos2upnr.png)
so the area of the first circle is 2
![2\pi](https://img.qammunity.org/2022/formulas/mathematics/college/s8tx2lp4i92tra1th9nd42hubveos2upnr.png)
now let find the second circle
Since the semi circle is twice the area of AB the diameter is 8 so the radius is 4.
Put it in the equation.
![(1)/(2) * \pi {4}^(2)](https://img.qammunity.org/2022/formulas/mathematics/high-school/276h549ykdumjgj1qu093fsu8gfgi95wqk.png)
![(1)/(2) * \pi * 16](https://img.qammunity.org/2022/formulas/mathematics/high-school/66yeakfe4km9gd71x0ox73x7odcmiqdzx5.png)
![8\pi](https://img.qammunity.org/2022/formulas/mathematics/college/w45xkyapjjmf6xtf01ll97cjr9c0rahxu2.png)
Now let find the third circle
Since it is twice the size of the second circle, the diameter is 16 and the radius is 8.
![(1)/(2) * \pi {8}^(2)](https://img.qammunity.org/2022/formulas/mathematics/high-school/wvayyudfqe9dzdc5d5pi24y119cr9gzx0h.png)
![(1)/(2) * 64\pi](https://img.qammunity.org/2022/formulas/mathematics/high-school/g0z47a2mdwsdo81xducl16l24wh3lhrbrr.png)
![32\pi](https://img.qammunity.org/2022/formulas/mathematics/high-school/zxtuqt30b2fj4m0zfagvyb9mdzwivytk0j.png)
Now let add the area of the semi circle
![32\pi + 2\pi + 8\pi = 42\pi](https://img.qammunity.org/2022/formulas/mathematics/high-school/b6z257aaa9a0bwnl47tokb6e5vdox1kamt.png)