In triangle DEF, find the missing side as an exact value:

8.60

Step-by-step explanation:

the diagram is optically misleading.

how can the 5 side be longer than the 7 side ?

but ignore that.

the important thing is that this is a triangle with a 90 degree angle.

so, we use Pythagoras' formula : a^2 + b^2 = c^2

we know a and b as 7 and 5.

so, the equation is 7^2 + 5^2 = c^2

=> 49 + 25 = c^2

=> 74 = c^2

=> the missing side length c is