3.1 Surface Area of Prisms October 25 2017

Lesson Outline What is surface area? What is a prism? How do you find surface area of common shapes? (Oct 25th) How do you find surface area of a prism? Drawing the nets of a 3D shape

What is Surface Area? The surface area is the total area that covers a three dimensional shape E.g. the surface area of a box can be found by unfolding it and flattening it out

What is a Prism A prism is a 3D object that has two parallel congruent polygons, with sides that are parallelograms In other words, a 3D object with 2 shapes on opposite sides, and four sided shapes in between them

Which of these are prisms?

What is a Prism ? Right Right Rectangular Triangular Prism Prism Prisms are named for the shapes on their sides ? Right Rectangular Prism Right Triangular Prism

What is a Prism Prisms are also named for whether the shapes on opposite ends are directly on top of each other.

What is a Prism Prisms are also named for whether the shapes on opposite ends are directly on top of each other.

Surface area of a flat shape How do I find the surface area of the rectangle below? What are two pieces of information I need, and what do I do with them?

Surface area of a flat shape Width Length Length x Width = Surface area of Rectangle

Surface area of a flat shape How do I find the surface area of the triangle below? What are two pieces of information I need, and what do I do with them?

Surface area of a flat shape Base x Height 2

Surface area of a flat shape Base x Height 2 Why divide by 2?

Surface area of a flat shape Base x Height 2 Notice that it is height not side

Surface Area of a Circle

Surface Area of a Circle Pi = 3.141592654… r = radius

Surface Area of a Circle 12 cm A = πr2 A = π(6)2 A = 36π A = 113 cm2

Math Connect Activity

Surface Area of a Parallelogram Why? Base x Height (NOT SIDE)

Surface Area of a 3D shape If we were to unravel a 3D object, it would be made up of multiple 2D shapes.

Activity (5 min) Using a ruler, find the surface area of two rectangular prisms You may use the ones provided or find your own

Surface Area of 3D Shape The formula of SA of rectangular prism 2 WH + 2 LW + 2 LH NOTE: It doesn’t matter which you make the length, height and width

Surface Area of 3D Shape 2 WH + 2 LW + 2 LH W = 22 cm H = 7.5 cm L = 5.5 cm = 2(22 cm)(7.5 cm) + 2(5.5 cm)(22 cm) + 2(5.5 cm)(7.5 cm) = 330 cm2 + 242 cm2 + 82.5 cm2 = 654.5 cm2

Drawing a Net If I unfolded this Toblerone package, what would it look like? What shapes would I have?

Drawing a Net What is a net? – a two dimensional pattern that can be folded to form a three dimensional shape

Surface Area of 3D Shape

Toblerone Activity (5 min) 15 cm 3.5 cm 2.4 cm Label the dimensions of the Toblerone package onto the net, then find the surface area

Homework