PLEASE ANSWER HONESTLY (PLEASE BE HELPFULL I HAVE BEEN STUCK ON THIS PROBLEM) WILL MARK BRANIEST IF CORRECT. (no links my computer is slow and no ctrl c ctrol v if possible

Answer:
No
Step-by-step explanation:
For this triangle to be a right triangle the following has to happen:
a^2 + b^2 = c^2
a=3, b=9, c= 12
3^2+9^2 does not equal 12^2
9+81 = 90 12^2 = 144
90 does not equal 144 so is not a right triangle
Answer:
see explanation
Step-by-step explanation:
Using converse of Pythagoras' identity
If the square of the longest side is equal to the sum of the squares on the other 2 sides then the triangle is right.
longest side = 12 , then 12² = 144
3² + 9² = 9 + 81 = 90 ≠ 144
Thus the triangle is not right.