Math challenge question?

a triangle has sides of length 6,7 and x where x is an integer. compute the number of values of s such that the traingle is acute. since it is acute , when the legs are x and 6 the hypotenuse is 7 x is the square root of 13. whe nthe legs are 6 and 7 and the hypotenuse is x, then x equals the square root of 85. then what do you do , SINCE IT IS ACUTE WHAT DO YOU DO NEXT, it is every integer less than the square roof of 85, but WHYis it everyhing greater than the square root of 13, remember it is acute