9514 1404 393
Answer:
 726 ft²
Step-by-step explanation:
The perimeter of the room is ...
 P = 2(L+W) = 2(18 +15) = 66 . . . . ft
Then the gross wall area (including windows) is ...
 A = LH = (66 ft)(8 ft) = 528 ft² . . . . gross wall area
The area of the 3 windows is ...
 A = 3×LW = 3×(6 ft)(4 ft) = 72 ft² . . . . window area
The area of the ceiling is ...
 A = LW = (18 ft)(15 ft) = 270 ft² . . . . ceiling area
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Then the net area to be painted is ...
 gross wall area + ceiling area - window area
 = 528 ft² +270 ft² -72 ft² = 726 ft²
The area that Marta will paint is 726 ft².
