Answer:
285 cm
Explanation:
perimeter of big triangle
base = 19 + 27
=46 cm
perimeter = base*height/2
=46*30/2
=1380/2
=690 cm
perimeter of not white not shaded triangle
base = 27 cm
height = 30 cm
perimeter = base*height/2
=27*30/2
=810/2
=405 cm
perimeter of shaded triangle = 690 cm - 405 cm
=285 cm