Answer:
It's an acute triangle.
Step-by-step explanation:
In a triangle ABC with longest side C:
If [tex]c^2>a^2+b^2[/tex] then ABC is acute
If [tex]c^2=a^2+b^2[/tex] then ABC is right
If If [tex]c^2<a^2+b^2[/tex] then ABC is obtuse
In this case A=3, B=5 and C=7. Let's see:
[tex]7^2 ? 3^2+5^2[/tex]
[tex]49 ? 9+25[/tex]
[tex]49 > 34 [/tex]
As 49 is bigger than 34, then ABC is acute.