Warm – Up: Wednesday 10/5 Describe the difference between the two rectangular prisms shown below The first one is a perfect cube because the measurements are all the same. A cube is made of 6 equal squares faces. The second one is a rectangular prism because the measurements are different. A rectangular prism is made of 6 rectangle faces.

What are the characteristics of a rectangle? What are the characteristics of a square? What are the characteristics of a rectangular prism? A rectangle is a 4 sided polygon with 4 right angles and OPPOSITE sides are congruent and parallel. A square is a 4 sided polygon with 4 right angles and ALL sides congruent. Opposite sides are parallel. A rectangular prism is a 3D figure made up of 6 faces that are either rectangles or squares.

Always, Sometimes, Never Squares are rectangles. Rectangles are squares. Cubes are rectangular prisms. Rectangular prisms are cubes. ALWAYS. To be a rectangle, opposites sides must be congruent and parallel, 4 right angles, and a polygon. These are also true from all squares. SOMETIMES. Rectangles don’t have to have all congruent sides. A square does! ALWAYS. Cubes are 3D figures that are made up of 6 square faces. Since squares are rectangles, cubes are rectangular prisms. SOMETIMES. If the faces of the rectangular prism are squares, it is a cube. If the faces are rectangles, it is not a cube.

Prisms Surface Area & Volume

A formula is just a set of instructions A formula is just a set of instructions. It tells you exactly what to do! All you have to do is look at the picture and identify the parts. Substitute numbers for the variables and do the math. That’s it! 

Either method will give you the same answer. Let’s take a look at rectangular prisms. Surface area can be found using the formula SA = 2lw + 2lh + 2wh OR Either method will give you the same answer. you can find the area for each face and add them up. Volume of a rectangular prism is V = lwh

Example: 7 cm 4 cm 8 cm SA = 2lw + 2lh + 2wh l = 8 w = 4 h = 7 V = lwh V = 8(4)(7) 2(8)(4) +2(8)(7) +2(4)(7) = V = 224 cm³ SA = 232 cm²

Surface Area and Volume Review

What is the minimum amount of gift wrap you would need to wrap a box that is 10 inches long, 8 inches wide, and 6 inches in height? SA= 2lw+ 2lh+2wh SA= 2(10)(8)+2(10)(6)+2(8)(6) SA= 160+120+96 SA= 376 in.2 of gift wrap

V= lwh V= 4(3)(1) V= 12 ft.3 of sand Approximately how much sand is needed to fill a sandbox that is 4 feet in length, 3 feet in width and 1 foot in height? V= lwh V= 4(3)(1) V= 12 ft.3 of sand

Approximately how much material would you need to recover a suitcase that is 20 inches in length, 6 inches in width, and 15 inches in height? SA= 2lw+ 2lh+2wh SA= 2(20)(6)+2(20)(15)+2(6)(15) SA= 240+600+180 SA=1,020in.2 of material

V= lwh V= 22(14)(10) V= 3,080 ft.3 of water How much water is needed to fill a rectangular pool with a length of 22 feet, width of 14 feet and height of 10 feet? V= lwh V= 22(14)(10) V= 3,080 ft.3 of water

Warm – Up: Thursday 10/6 The surface area of a cube is 216 square inches. What is the length of each side of the cube?     6 in.

Let’s check your homework!

Alright, now let’s work on some more practice.

If you don’t finish these in class they are homework. Now you finish #4 & # 5 If you don’t finish these in class they are homework.

# 4 # 5