28Area and perimeter, L-shape

An L-shaped room is a 10 m by 8 m rectangle with a 4 m by 3 m rectangle cut out of one corner. Find the area and the perimeter of the room.

The area is 80 − 12 = 68 m², and the perimeter is 38 m. You get the area by taking the full 10×8 rectangle (80 m²) and subtracting the 4×3 corner that's cut out (12 m²). For perimeter, walk around all six outer edges: 10 + 8 + 4 + 3 + 6 + 7 = 38 m.