Foundations for College Math (MAP4C) · Geometry and Trigonometry

Net area of a wall with cutouts

Find the paintable area of a wall after subtracting windows/doors, and (at higher difficulty) the number of paint cans needed. Unlimited questions, five difficulty levels, and a full worked solution every time — free.

Practice this skill Curriculum: MAP4C-GT1

Try one

A renovator is working on a wall 8 m long and 3 m high, with a window 2 m by 1 m. What is the area that actually needs paint (or drywall)?

Answer: 22

See one solved, step by step

A drywall installer is working on a wall 10 m long and 3 m high, with a window 2 m by 1 m and a door 2 m by 1 m. What is the area that actually needs paint (or drywall)?

📘 Worked solution
1Wall area: 10 · 3 = 30 m2The full wall is a rectangle, so multiply length by height.
2Cutout area: (2 · 1) + (2 · 1) = 2 + 2 = 4Add up the area of every window or door — none of that gets painted.
3Net area: 30 - 4 = 26 m2Subtract the cutout area from the full wall area to get the paintable area.

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