If there is an image I cannot see it, so I solved it two different ways:
If 24 is the hypotenuse and 6 is one of the other sides:
6^2+x^2=24^2
36+x^2=576
x^2=540
x~23
If 24 is not the hypotenuse and is a side along with 6:
24^2+6^2=x^2
576+36=x^2
sqrt(612)=x
x~25