Answer: 6units
Step-by-step explanation:
Since it is a regular polygon, and it has 3 equal sides it means the polygon is a quadrilateral.
From the diagram,
5 - 2x = -4x + 9 ( side of quadrilateral )
Solving for x in the equation
-2x + 4x = 9 - 5 ( collection of like terms in simple linear equation )
2x = 4
Divide through by the coefficient of x which is 2
x = 2.
Therefore, the perimeter of the polygon which equals to the total length of the polygon is
Perimeter = 2 + 2 + 2
= 6units