Surface Area

Refers to how many square units it takes to cover a surface 4 squares wide 4 squares long

Surface area of a Rectangle or Square Formula A= Length times width Or A = L X W

Surface area of a Rectangle or Square Example A= LW = (3m)(5m) = 15 m² 3 meters 5 meters 1 meter

Try 9 cm 2 cm A = LW = (9 cm)(2cm) = 18 cm²

Irregular Shapes 12 m 5 m 4 m 6m 3m 1.Cut the object into regular shapes 2.Apply your formula to each shape 3.Add all the shapes together

Irregular Shapes 12 m 5 m 4 m 6m 3m 1.Give each shape a name and apply it to the formula 2.Example Aa= LW Ab= LW Ac=LW

Irregular Shapes 12 m 5 m 4 m 6m 3m 12 m 3 m Aa= LW = (12m)(3m) = 36m²

Irregular Shapes 12 m 5 m 4 m 6m 3m Ab= LW = (5m)(3m) = 15m² 5 m 3m

Irregular Shapes 12 m 5 m 4 m 6m 3m Ac= LW = (4m)(4m) = 16m² 4 m

Irregular Shapes Add all the areas together to get a final answer Aa + Ab + Ac = 36m² + 16m² 15m² = 67m²

Irregular Shapes Continued Sometimes you may have to subtract two areas. What is the area of the square green square that is Remaining? 5 km

Irregular Shapes Continued What do we know? -it’s a square which means all sides are 5km long What is the diameter of the circle? - it’s the width of the square 5 km

Irregular shapes As(s for square) = LW = (5km)(5km) = 25 km² Ac( for circle) = π r² = (3.14)(2.5m)² = km²

Irregular Shapes Subtract the two areas to get a final answer. 25 km² km² km²