b.
First squared the following conversion factor: 1 ft = 12 in, as follow:
![\begin{gathered} 1ft=12in \\ (1ft)^2=(12in)^2 \\ 1ft=144in^2 \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/qdpyl089znx0mrnte84r2auhifk8zj15rg.png)
Then, use the previous result as a conversion factor to convert 80.0ft^2, as follow:
![80.0ft^2\cdot(144in^2)/(1ft^2)=11520in^2](https://img.qammunity.org/2023/formulas/physics/college/w9khr8dq6ddpxxneo7x15nit77wsc80384.png)
Now, consider that 1 m = 39.3701 in, then, if you squared you obtain:
![\begin{gathered} 1m=39.3701in \\ (1m)^2=(39.37in)^2 \\ 1m^2=1550.004774in^2 \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/2r9aysl57k55rku2lmzrq3zrwq512inkt4.png)
use the previous result as a conversion factor:
![11520in^2\cdot(1m^2)/(1550.004774in^2)\approx7.43m^2](https://img.qammunity.org/2023/formulas/physics/college/rubvonp6ebejkm3mvbglz7ofgf8nmlo1jy.png)
Hence, 80.0ft^2 is approximately 7.43 m^2