Example
: Determine whether a triangle with sides 12 cm, 14 cm and 18 cm is an acute, right or obtuse triangle.
Solution:
We choose the two shorter sides to be a
and b and the longest side to be
c.So a
= 12, b
= 14 and c
= 18. a2
+ b2
= 122
+ 142
= 144 + 196 = 340 c2 = 182
= 324 340 < 34 → c2
< a2
+ b2
, and so the triangle is an acute triangle.
