Answer: OPTION B
Explanation:
Calculate the area the triangles (Both are equal, then you can multiply the area of one of them by 2):
![A_t=2((b*h)/(2))](https://img.qammunity.org/2020/formulas/mathematics/middle-school/u3fu7ug4pkquk58gsl0668mmvx24555y0f.png)
Where b is the base and h is the height:
![A_t=2((6cm*8cm)/(2))=48cm^(2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/zkyirhwze6bz5m5tbr362cxwbt9ricp468.png)
Calculate the area of the rectangles that are equal (you can multiply the area of one of them by 2):
![A_(r1)=2lw](https://img.qammunity.org/2020/formulas/mathematics/middle-school/afmur10645jn6utxctm90ze5nhfmv7x950.png)
Where l is the length and w is the width:
![A_(r1)=2*12cm*8cm=192cm^(2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/z3s2ncn94g3r8ed6itp5lm0wd824i0upnr.png)
Calculate the area of the other rectangle:
![A_(r2)=12cm*6cm=72cm^(2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/n6fslcodrpu3z2le83sbz25s6c4z7e5f56.png)
Add the areas. Then, the result is:
![A{prism}=48cm^(2)+192cm^(2)+72cm^(2)=312cm^(2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/v4i4e2q56xdbj6w7ayhhpetqs6awnc6kxh.png)