1 / 15

Objectives: Find the area and perimeter of irregular geometric figures

Section 1-7 Perimeter, Area, Circumference SPI 21B: solve equations to find length, width, perimeter and area SPI 32L: determine the area of indicated regions involving figures SPI 41A: determine the perimeter & area of 3 or 4 sided plane figures.

lynley
Télécharger la présentation

Objectives: Find the area and perimeter of irregular geometric figures

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Section 1-7 Perimeter, Area, Circumference SPI 21B: solve equations to find length, width, perimeter and areaSPI 32L: determine the area of indicated regions involving figuresSPI 41A: determine the perimeter & area of 3 or 4 sided plane figures • Objectives: • Find the area and perimeter of irregular geometric figures • Find the area and perimeter of regular geometric figures • Apply area and perimeter formulas to real world situations • Discover relationships between different geometric figures • Find Volume of rectangular solids Outline of Lesson Vocabulary Common formulas for geometric figures Irregular geometric figures Volume of Rectangular Solids

  2. Vocabulary • Perimeter: • the sum of the lengths of the sides of a polygon • fence around a plot of land • Circumference: • the distance around the outside of a circle • the distance around the earth

  3. Vocabulary (cont) • Area: • number of units (squared) enclosed by the perimeter Amount of carpet needed for a room • number of units enclosed by the circumference (circle) Amount of material needed to construct a trampoline

  4. Vocabulary (cont) Base: bottom of a figure height Height/Altitude: line perpendicular to base extending to the top of the figure base Diameter: a straight line connecting the center of a circle with two points on its perimeter Radius: the length of a line segment between the center and circumference of a circle

  5. Some Common Formulas Perimeter: P = 4s Square Area: A = s2 s = side Perimeter: P = 2b + 2h Rectangle Area: A = bh b = base h = height

  6. Some Common Formulas (cont) Circumference: C = d or C = 2r Circle d = diameter r = radius Area: A = r2 Triangle Perimeter: use the distance formula h b = base h = height b Area: A = ½ bh

  7. Real-World Connection Fencing. Your pool is depicted in the diagram below. You want to build a fence around the deck. How much fencing will you need? Width of pool and deck: 15 + 3 + 3 = 21 feet Length of pool and deck: 20 + 3 + 3 = 26 feet Solve: P = 2w + 2L Formula = 2(21) + 2(26) Substitute = 94 Simplify You will need 94 feet of fencing.

  8. Real-World and Finding Circumference Biology. In the Pacific Northwest, a red fox has a circular home range with a radius of about 718 meters. What is the area of the home range of a red fox? A = r2 Formula A = (718) 2 Substitute = 1,619,566 Simplify

  9. Finding Perimeter in the Coordinate Plane Find the perimeter of ∆ABC. Find the length of each side. Side AB. |5 – (-1)| = 6 Side BC. |6- (-2)| = 8 Side AC. AB + BC + AC = 6 + 8 + 10 = 24. The perimeter is 24 units.

  10. Finding Area of a Rectangle You are designing a banner for a music festival. The banner will be 4 ft wide by 7 feet high. How much material will you need? Area of Rectangle = bh Convert yards to feet: 7 yards = 21 feet Substitute values into formula A = 4(21) = 84 You will need 84 square feet (ft2) of material.

  11. Finding Area of Irregular Figures Find the area of the figure. Separate the figure into rectangles. Use Area of a Rectangle Formula A1 = 6 ∙ 2 = 12 Total Area = 12 + 8 + 4 = 24 cm2 A2 = 4 ∙ 2 = 8 A3 = 2 ∙ 2 = 4

  12. Finding Area of Irregular Figures Estimate the area of an Irregular Geometric Figure • Count the number of square units, by marking the diagram • Estimate partial units • Combine partial units to create whole units • Add the units to estimate area

  13. Estimate the Area of the Irregular Geometric Figure Mark all the whole units 1 1 1 1 .5 • Mark the partial units • estimate 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 .5 1 1 1 1 1 1 1 The area is approximately 27 units2

  14. Volume of Rectangular Solids Volume the amount of 3-dimensional space occupied by an object How much product a box of cereal contains Volume Formula V = lwh

  15. Apply Volume Formula of Rectangular Solids A die is a cube molded from hard plastic.  The edge of a typical die measures 0.62 in.  Dice are usually produced in a mold which holds 100 die at one time.  To the nearest cubic inch, how much plastic is needed to fill this large mold? V = l · w · h = (.62)(.62)(.62) = .238 in3 For 100 dice = 100 x .238 = 23.8 or approximately 24 cubic inches

More Related