Answer:
Step-by-step explanation:
defining: a = 4.5 cm ; b = 6 cm ; c = 8.5 cm
Then by cosines law (see jpg adjunt):

Apliying arcCosine(): A = 30.4°
Doing the same to B:

Apliying arcCosine(): B = 38.3°
Since, , B and C, has to:
A+B+C = 180° ---> C = 111.3°
This means: the triangule has two angules <90° and one >90°, wich is the definition of <em>obtuse triangle.</em>
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