geometry
posted by It .
A triangle has sides x,x+7 , x+ 8. The value of x must fall between what boundaries to make this an obtuse triangle?

any side of a triangle is less than the sum of the other two sides.
x < x+7 + x+8
15 < x
no problem there
x+7 < x + x+8
1 < x
no problem there
x+8 < x + x+7
1 < x
so, as long as x is at least 1, the three values could form a triangle.