Find an integer, x, such that 5, 10, and x represent the lengths of the sides of an acute triangle.

a.
4
b.
5
c.
6
d.
11

X = 4 and x = 5 can not be a triangle, because:
4 + 5 = 9 < 10 and 5 + 5 = 10. So it can be C ) or D ).
We will use the Pythagorean inequality:
x² > 10² - 5² ( for an acute triangle )
x² > 100 - 25
x² > 75
x > 5 √ 3
x > 8.66

D ) 11

The answer would be bad because it's a number for both 5 & 10