Post on 30-Dec-2015
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Holt McDougal Geometry
1-5 Using Formulas in Geometry
BellworkWrite a definition of the angle pairs below,
and draw a diagram to represent each pair.
Holt McDougal Geometry
1-5 Using Formulas in Geometry
Apply formulas for perimeter, area, and circumference.
Rigor
RelevanceFormulas help determine the amount needed and cost of materials.
Holt McDougal Geometry
1-5 Using Formulas in Geometry
The perimeter (P) is the sum of the side lengths of the figure. Units for length (ft, m, in)
The area (A) is the number of square units of a given size that exactly cover the figure. Square units (ft2, m2, in2)
Holt McDougal Geometry
1-5 Using Formulas in Geometry
Rectangle
A = bhb=base, h=height
h
b
Triangles Circles
A = ½ bhA = r2
Circumference (C)C = 2r C = d
r = radiusd = diameter
Holt McDougal Geometry
1-5 Using Formulas in Geometry
The base b can be any side of a triangle. The height h is a segment from a vertex that forms a right angle with a line containing the base.
Holt McDougal Geometry
1-5 Using Formulas in Geometry
Find the perimeter and area of each figure.
Example 1: Finding Perimeter and Area
Holt McDougal Geometry
1-5 Using Formulas in Geometry
The Texas Treasures quilt block includes 24 purple triangles. The base and height of each triangle are about 3in. Find the approximate amount of fabric used to make the 24 triangles.
Example 2: Crafts Application
If the fabric costs $8 per square foot, how much will the fabric cost?
Holt McDougal Geometry
1-5 Using Formulas in Geometry
Example 3: Calculate the Circumference and Area of a Circle
Calculate C and A of the 12in pizza in terms of and to the nearest tenth.
Holt McDougal Geometry
1-5 Using Formulas in Geometry
Composite Figures• Composite figure– a region made of
common, non-overlapping shapes
• Area Addition Postulate – the area of a region is the sum of the areas of its non-overlapping parts
Holt McDougal Geometry
1-5 Using Formulas in Geometry
Example 4: Calculate the area of the shaded regions below.
Holt McDougal Geometry
1-5 Using Formulas in Geometry
Example 5: Real Life Application
A) If a runner were to run 4 laps on the outer track, about how far would he run? Use 3.14 for .
B) The school re-sods the grass inside the track. About how many square feet should the school buy? Use 3.14 for .
Holt McDougal Geometry
1-5 Using Formulas in Geometry
Classwork from the Textbook
Homework from the Core Book
Heading: Section 1-5 Classwork pg 38-39
Assignment: pg 38 #3 – 9pg 39 #20 – 22, 26, 30
Core book 1-5 Problem Solving: pg 30 #1 – 6
Due Thursday for periods 1, 3, & 5Due Friday for periods 2, 4, & 7