1. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 End of Lecture / Start of Lecture mark

2. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 Warm Up Evaluate. Round to the nearest hundredth. 1. 13 2 2. 5.5 2 3. 4. 5. 3 2 () 6. (3) 2 169 30.25 8 7.35 28.27 88.83

3. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 Midpoint Perpendicular Lines Perpendicular bisector Angle Bisector Vocabulary 2

4. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 Properties of Good Definitions It is precise (Do not use Large, Sort of, and Some ) A good definition uses clearly understood terms. It states what the term is, rather than what it is not. 3

5. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 A Midpoint of a segment is a point that divides a segment into two congruent segments. Perpendicular lines are two lines that intersect to form right angles. The symbol is ABC xy z J K Definitions: 4

6. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 Definitions Perpendicular Bisector of a segment is a line, segment or a ray that is perpendicular to a segment at its midpoint. xy z J K 5

7. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 Angle bisector is a ray that divides an angle into two congruent angles. O A B C TOOLS OF GEOMETRY : LESSON 1-5 6

8. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 12

9. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 perimeter diameter area radius base circumference height pi Vocabulary

10. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 The perimeter P of a plane figure is the sum of the side lengths of the figure. The area A of a plane figure is the number of non-overlapping square units of a given size that exactly cover the figure.

11. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5

12. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 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. The height may be a side of the triangle or in the interior or the exterior of the triangle.

13. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 Perimeter is expressed in linear units, such as inches (in.) or meters (m). Area is expressed in square units, such as square centimeters (cm 2 ). Remember!

14. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 Find the perimeter and area of each figure. Example 1A: Finding Perimeter and Area = 2(6) + 2(4) = 12 + 8 = 20 in. = (6)(4) = 24 in 2

15. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 Find the perimeter and area of each figure. Example 1B: Finding Perimeter and Area = (x + 4) + 6 + 5x P = a + b + c = 6x + 10 = 3x + 12

16. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 TEACH! Example 1 P = 4s Find the perimeter and area of a square with s = 3.5 in. A = s 2 P = 4(3.5) A = (3.5) 2 P = 14 in.A = 12.25 in 2

17. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 A Quilt

18. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 The Queens Quilt includes 12 blue triangles. The base and height of each triangle are about 4 in. Find the approximate amount of fabric used to make the 12 triangles. Example 2: Crafts Application The area of one triangle is The total area of the 12 triangles is 12(8) = 96 in 2.

19. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 TEACH! Example 2 Find the amount of fabric used to make four rectangles. Each rectangle has a length of in. and a width of in. The area of one rectangle is The amount of fabric to make four rectangles is

20. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 In a circle a diameter is a segment that passes through the center of the circle and whose endpoints are on a circle. A radius of a circle is a segment whose endpoints are the center of the circle and a point on the circle.

21. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 The circumference of a circle is the distance around the circle.

22. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 The ratio of a circle’s circumference to its diameter is the same for all circles. This ratio is represented by the Greek letter  (pi). The value of  is irrational. Pi is often approximated as 3.14 or.

23. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 Example 3: Finding the Circumference and Area of a Circle Find the circumference and area of a circle with radius 8 cm. Use the  key on your calculator. Then round the answer to the nearest tenth.  50.3 cm 201.1 cm 2

24. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 TEACH! Example 3 Find the circumference and area of a circle with radius 14m.  88.0 m 615.8 m 2

25. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 Lesson Quiz: Part I Find the area and perimeter of each figure. 1. 2. 3. 23.04 cm 2 ; 19.2 cm x 2 + 4x; 4x + 8 10x; 4x + 16

26. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 Lesson Quiz: Part II Find the circumference and area of each circle. Leave answers in terms of . 4. radius 2 cm 5. diameter 12 ft 6. The area of a rectangle is 74.82 in 2, and the length is 12.9 in. Find the width. 4 ² cm; 4 cm 2 36 2 ft; 12 ft 2 5.8 in

27. Geometry CH 1-5 Good Definitions TOOLS OF GEOMETRY : LESSON 1-5 End of Lecture / Start of Lecture mark 17