Answer:
![B)\ 6ft,8ft,12ft](https://img.qammunity.org/2021/formulas/mathematics/high-school/brn0c2oicd22f22h40fkwjoxzoprlwqlhe.png)
Explanation:
Pythagorean Theorem : In a right triangle, square of hypotenuse is equal to the sum of the squares of the other sides.
![(A)\ 3cm,4cm,5cm\\5^2=25\\3^2+4^2=9+16=25\\5^2=3^2+4^2](https://img.qammunity.org/2021/formulas/mathematics/high-school/ayky0kjytfimiyaaov087q9391u8bieg38.png)
Hence these sides represent a right triangle.
![(B)\6ft.8ft,12ft\\12^2=144\\6^2+8^2=36+64=100\\12^2\\ot=6^2+8^2](https://img.qammunity.org/2021/formulas/mathematics/high-school/qm6o8jv0fwp6ea94de6maz6q3f3mfgg1qx.png)
Hence this does not represent a right triangle.
![(C)\27cm,36cm,45cm\\45^2=2025\\27^2+36^2=729+1296=2025\\45^2=27^2+36^2](https://img.qammunity.org/2021/formulas/mathematics/high-school/gnjiyp3iojqdjiedyn37v45d1aek7di207.png)
This represents a right triangle.