Presentation on theme: "Construction Geometry"— Presentation transcript:
1Construction Geometry Right Rectangular PrismsSurface AreaVolume
2Rectangular PrismsRight rectangular prisms are 3 dimensional rectangles.We often think of them as closed boxes or, in construction, examples would be rectangular concrete slabs.
3Rectangular PrismsA right prism has bases which meet the lateral faces at right angles.A right rectangular prism has bases which are rectangles and form right angles with the other faces.
4Surface AreaSurface area can be thought of as the amount of wrapping paper, with no overlap, needed to cover a box.
5Surface Area Split into 3 separate rectangles. Front/back sides Top/bottom sidesRight/left sidesFind the areas of each (LxW) and double.Sum the areas.10”8”8 “6”10 in8 inA = 80 sq in10 in6 inA= 60 sq in6 in8 inA = 48 sq in
6Surface Area 2(80) = 160 sq. in. 2(60) = 120 sq. in 2(48) = 96 sq. in 10”8”8 “6”10 in8 inA = 80 sq in10 in6 inA= 60 sq in6in8 inA = 48 sq in
7CubeA cube is a right rectangular prism. All its sides are congruent squares.All 6 faces have the same area.So the surface area of a cube = x (area of one face).Face = (4 x 4) = 16 ft2Surface area = 6(16) = 96 ft24 ft
8Surface AreaThe surface area of a rectangular prism can be found using a formula.SA= 2(LW + LH + WH)This formula is found on the Math Reference Sheet.
9Formula for a rectangular prism SA = 2(LW+ LH + WH) Surface AreaFormula for a rectangular prismSA = 2(LW+ LH + WH)WidthHeightLength
10Practice #1Determine the surface area of the right rectangular prism using the formula.SA = 2(LW+ LH + WH)2 mm10 mm5 mm