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1.7 Introduction to Perimeter, Circumference, & Area. Geometry Mrs. Spitz Fall 2005. Standards/Objectives:. Standard 3: Students will understand geometric concepts and applications. Objectives: Find the perimeter and area of common plane figures. Use a general problem-solving plan.
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1.7 Introduction to Perimeter, Circumference, & Area Geometry Mrs. Spitz Fall 2005
Standards/Objectives: Standard 3: Students will understand geometric concepts and applications. Objectives: • Find the perimeter and area of common plane figures. • Use a general problem-solving plan.
Assignment: • pp. 55-57 #1-47 and practice quiz on pg. 58 #1-10 all. • EXTRA CREDIT– I will use this to make up an assignment you are missing (some of you are missing a few). You must show ALL WORK – NO MAGICIANS IN ALLOWED, PLEASE. • Chapter 1 Review – pp. 60-62 #1-33 all
Rectangle W (width) • Perimeter P=2l +2w • Area A=lw l (length)
Square • Perimeter P=4s • Area A=s2 S (side)
Triangle a c • Perimeter P=a+b+c • Area A= ½ bh h (height) b (base)
Circle • Diameter d=2r • Circumference C=2πr • Area A=πr2 diameter radius ** Always use the π button on the calculator; even when the directions say to use 3.14.
Example: Find the perim. & area of the figure. • P=2l +2w P=2(5in)+2(3in) P=10in+6in P=16in • A=lw A=(5in)(3in) A=15in2 5 in 3 in
Ex: Find the perim. & area of the figure. • P=4s P=4(20m) P=80m • A=s2 A=(20m)2 A=400m2 20 m
Ex: Find the perim. & area of the figure. • P=a+b+c P=5ft+7ft+6ft P=18 ft • A= ½ bh A= ½ (7ft)(4ft) A= ½ (28ft2) A= 14ft2 5 ft 4 ft 7 ft 6 ft
Ex: Find the circumference & area of the circle. • C=2πr C=2π(5in) C=10π in C≈31.4 in • A=πr2 A=π(5in)2 A=25π in2 A≈78.5 in2 10in
Reminders: • Test after this section. • Start doing your definitions for chapter 2 – Do all of them including the review. • Start doing your postulates/theorems (green boxes) – pp. 73, 88, 89, 90, 96, 98, 102, 109, 110, 111, 112,