3. Let’s start in the beginning… Before you can do surface area or volume, you have to know the following formulas. CircleA = π r² C = πd RectangleA = lw TriangleA = ½ bh

4. Surface Area What does it mean to you? Does it have anything to do with what is in the inside of the prism?

5. Definition Surface Area – is the total number of unit squares used to cover a 3-D surface.

6. Find the SA of a Rectangular Solid Front Top Right Side A rectangular solid has 6 faces. They are: Top Bottom Front Back Right Side Left Side Which of the 6 sides are the same? Top and Bottom Front and Back Right Side and Left Side We can only see 3 faces at any one time.

7. Surface Area of a Rectangular Solid Front Top Right Side We know that Each face is a rectangle. and the Formula for finding the area of a rectangle is: A = lw Steps: Find: Area of Top Area of Front Area of Right Side Find the sum of the areas Multiply the sum by 2. The answer you get is the surface area of the rectangular solid.

8. Find the Surface Area of the following: 12 m 8 m 5 m Top Front Right Side Front Top Right Side Find the Area of each face: 12 m 5 m 12 m 8 m 5 m 8 m A = 12 m x 5 m = 60 m 2 A = 12 m x 8 m = 96 m 2 A = 8 m x 5 m = 40 m 2 Sum = 60 m 2 + 96 m 2 + 40 m 2 = 196 m 2 Multiply sum by 2 = 196 m 2 x 2 = 392 m 2 The surface area = 392 m 2

9. A.22 in 2 B.36 in 2 C.76 in 2 D.80 in 2 Find the surface area of the rectangular prism.

10. Nets A net is all the surfaces of a rectangular solid laid out flat. Top Right Side Front 10 cm 8 cm 5 cm Top Bottom Front Back Right SideLeft Side 10 cm 5 cm 8 cm 5 cm

11. March 17, 2016 Apothem The perpendicular distance from the center of a regular polygon to one of its sides. Radius Apothem

12. Another Way to Find the Area The area of the hexagon is equal to the area of one triangle multiplied by the number of triangles, n. Area = (Area of one  )  (Number of  s)

13. Area of one triangle Radius Apothem s r a This is the Area of only one triangle.

14. Area of one triangle s r a Remember, there are n triangles. The total area then is

15. Perimeter s r a The perimeter of the hexagon is s  n. p = s  n s s s s s

16. Area of a Regular Polygon a = apothem p = perimeter This formula works for all regular polygons regardless of the number of sides.