Answer:
B- 3 by 7 by 9 is the only right answer.
Step-by-step explanation:
What is a triangle?
A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry. A triangle with vertices A, B, and C is denoted.
Basic rule:
A triangle must be tri-sided, means it must have three sides which is only possible if the sum of the smaller two sides is greater than the third side. Otherwise, a triangle is not physically possible.
A- 2+3 = 5 hence not a triangle.
B- 3+7 > 9 hence a triangle.
C- 4+5 < 9.5 hence not a triangle.
D- 5+6 < 12 hence not a triangle.
