Answer:
![\large\boxed{C.\ (25+25\sqrt3)\ in^2}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/3255qdhekclf8odbdmmp281whdr4rqrjmx.png)
Explanation:
We have the square and four equilateral triangles.
The formula of an area of a squre:
![A_S=a^2](https://img.qammunity.org/2020/formulas/mathematics/middle-school/axjx877ztoahtg7kfwx53wb1gtqb8i1krv.png)
a - length of side
The formula of an area of an equilateral triangle:
![A_T=(a^2\sqrt3)/(4)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/n6pkozlyrcx1qtxitxuo6nmgpxtghxsx8k.png)
a - length of side
Clculate the areas:
SQURE:
![A_S=x^2\ in^2](https://img.qammunity.org/2020/formulas/mathematics/middle-school/9zku2sjmwltu2z759ks4sqpkznrkhhm6v4.png)
TRIANGLE:
![A_T=(x^2\sqrt3)/(4)\ in^2](https://img.qammunity.org/2020/formulas/mathematics/middle-school/f0pm0hzlmsk9ukq22aydj4e53msdk55qtv.png)
The SURFACE AREA of a square pyramid:
![S.A.=A_S+4A_T\\\\S.A.=x^2+4\cdot(x^2\sqrt3)/(4)=x^2+x^2\sqrt3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/hucyo4ya7judjrq8gyq6ri9rmyz38xbinu.png)
Put x = 5:
![S.A.=5^2+5^2\sqrt3=(25+25\sqrt3)\ in^2](https://img.qammunity.org/2020/formulas/mathematics/middle-school/1wiv2kgpi3fnpx15na18hbsy3v2yj2xy9y.png)