Presentation on theme: "1.7 Perimeter, Circumference, & Area"— Presentation transcript:
1 1.7 Perimeter, Circumference, & Area WHAT’S IMPORTANT:--Be able to find the perimeter & area of common plane figures.--Be able to use a problem solving plan.
2 On the following slides, you will see the perimeter, circumference, and area formulas for some basic geometric shapes. We will use these formulas throughout the lesson.Perimeter & circumference use units such as centimeters (cm), meters (m), inches (in), feet (ft), yards (yd), & miles (mi).The measurements of area use units such as square centimeters (cm2), square inches (in2), & so on.
5 9.7 in5.2 sq. in.15.7 cm19.63 sq. cm.547.2 mmsq. ft.
6 Example Find the perimeter & area of the rectangle shown P = 2x + 2yP = 2(13) + 2(4)P =P = 34 in.A = xyA = 13(4)A = 52 in24 in.13 in.
7 Example: The diameter of a circle is shown. find the radius Example: The diameter of a circle is shown. find the radius. then use that to find the circumference and area.r = (1/2)dr = (1/2)(14)r = 7in.C = 2∏rC = 2∏(7)C = 2(3.14)(7)C = in.A = ∏r2A = (3.14)(72)A = (3.14)(49) = in214 in.F
8 Example Plot the Points & Find the area & perimeter of the triangle defined by D(1,2), E(6,2), & F(3,5)Plot the points.Draw the height from point F to the base DE. Label the point GPoint G has the coordinates (3,2)
9 Cont. Example...To find the area, we need to find the lengths of the base (DE) & the height (FG)DE = = 5FG = = 3A = (1/2)A = (1/2)(5)(3)A = (1/2)(15)A = 7.5 sq. units
10 Plot the Points & Find the area & perimeter of the triangle defined by D(1,2), E(6,2), & F(3,5) We need to find the lengths of all sides.We know the base is 5 unitsNow we must find the lengths of EF & DF.
11 Plot the Points & Find the area & perimeter of the triangle defined by D(1,2), E(6,2), & F(3,5) Add to find the perimeterPerimeter = units
12 find the area of the figure below Draw a horizontal line to separate the figure into 3 non-overlapping figures: a rectangle & 2 squares.
13 Find each area by adding Area of the RectangleA = bhA = (15)(5)A = 75Area of the SquareA = s 2A = (5)2A = 25Add the areasA =A = 125 ft 2Therefore the area of the figure is 125 ft 2.