Answer:
(Satellite images of both the buildings on a single coordinate grid are shown in the ATTACHMENT)
MARCI SHOULD WIN
AREA OF MUSEUM > AREA OF SCHOOL
Explanation:
Find the area of School in Grid squares:

Area of School = 20 Grid squares*10*10
Area of School = 2000 m²
Find the area of Museum in Grid squares:

Area of Museum = 9п grid squares
Area of Museum = 2826 m²
AREA OF MUSEUM > AREA OF SCHOOL