It’s 10
In triangle ABC:
3^2+4^2= c^2
9+16=25
Square root of 25 is 5, so hypotenuse of triangle ABC is 5.
For triangle DEF, not that the given side is 8, which twice the amount of four. To find the other adjacent side of the triangle, we will multiply 3 by 2 because that is what we did with the 4. by doing this we can conclude that our other side is of the triangle is 6 Then, we have this pythagorean theorem to solve for FD:
8^2+6^2= C^2
64+36=100
C^2=100
The square root of the 100 is 10, therefore the length of side FD is 10.