21.6 units
Calculate the length of the 2 inclined sides using the distance formula
d = √(x₂ - x₁ )² + (y₂ - y₁ )²
with (x₁, y₁ ) = (- 3, 3 ) and (x₂, y₂ ) = (3, 4 )
d = √(3 + 3 )² + (4 - 3)² = √(36 + 1 ) = √37
repeat for (x₁, y₁ ) = (- 3, 3 ) and (x₂, y₂ ) = (3, - 3 )
d = √(3 + 3 )² + (- 3 - 3 )² = √(36 + 36 ) = √72
the vertical side has a length of 7 units
perimeter = √37 + √72 + 7 = 21.6 ( nearest tenth of a unit )
