Art of Problem Solving

2005 iTest Problems/Problem 18

Problem

If the four sides of a quadrilateral are $2, 3, 6$, and $x$, find the sum of all possible integral values for $x$.

Solution 1

The sum of the 3 smallest sides must be greater than the largest side. Thus, $x$ must satisfy the following two inequalities: $2+3+x>6$ and $2+3+6>x$. Solving, we find (respectively) that $x>1$ and $x<11$. Therefore, our answer is $2+3+4+5+6+7+8+9+10=\boxed{54}$.

See Also

2005 iTest (Problems, Answer Key)
Preceded by:
Problem 17
Followed by:
Problem 19
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 TB1 TB2 TB3 TB4