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RETEST

RETEST. Must make corrections on all questions that are incorrect on a separate sheet of paper. MUST rewrite all questions as a statement. DO NOT just give me letter answers. T/F questions must be rewritten as true statements. Staple to original test and turn it in by Monday 5/14

kenyon-anthony
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RETEST

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  1. RETEST • Must make corrections on all questions that are incorrect on a separate sheet of paper. • MUST rewrite all questions as a statement. DO NOT just give me letter answers. T/F questions must be rewritten as true statements. • Staple to original test and turn it in by Monday 5/14 • Take retest after corrections are signed off on. The retest will be fill in the blank not M/C.

  2. Areas of Polygons COURSE 3 LESSON 8-7 (For help, go to Lesson 4-6.) Find the area of each figure. 1.2. 3. 2.A = l • w = 2.7 • 2 A = 5.4 m2 3. A = s2 = 72 A = 49 ft2 Solutions 1.A = l • w = 10 • 8 A = 80 cm2 8-7

  3. AREA 4 AREA- Area is the number of square units inside a figure. 3 FORMULA- Directions (equation) for solving a problem. A rectangle = l x w A square = s2 A = l x w A = 3 x 4 A = 12 sq units

  4. AREA Area of a Parallelogram- can’t use length x width Height AParallelogram = b x h Base

  5. Use the area of a parallelogram formula. A = bh A = bh Substitute for b and h. = (15) (11) = (32) (20) Multiply. = 165 cm2 = 640 in.2 Areas of Polygons COURSE 3 LESSON 8-7 Find the area of each parallelogram. a. b. 8-7

  6. AREA Area of a Triangle- There is a base and height, but that is already the formula of a parallelogram h What if we copy and flip the same triangle and make a parallelogram? b We can find the area of the whole parallelogram, but we only want half of it. That will give us the area of the triangle

  7. 1 2 A = bh Use the area of a triangle formula. 1 2 = • 36 •21 Substitute 36 for b and 21 for h. = 378 Multiply. Areas of Polygons COURSE 3 LESSON 8-7 Find the area of the triangular part of the doghouse. The area of the triangular part of the doghouse is 378 in.2. 8-7

  8. AREA Area of a Trapezoid- any ideas?????? Base2 Now it’s a parallelogram It’s AREA would be: A = (base1 +base2)xheight height Base1 Base2 + We don’t want the whole area, only half of it!

  9. 1 2 A = h(b1+b2) Use the formula. 1 2 Substitute 4.4 for h, 6.7 for b1, and 9.3 for b2. = (4.4) (6.7 + 9.3) Simplify. = 35.2 Areas of Polygons COURSE 3 LESSON 8-7 Find the area of the trapezoid. The area of the trapezoid is 35.2 in.2. 8-7

  10. AREA HW: 8-7 # 1-9, & 15 Show formula, substitution and answer with units for full credit

  11. Areas of Polygons COURSE 3 LESSON 8-7 Pages 444–446 Exercises 1. 50 cm2 2. 40 in.2 3. 60 cm2 4. 20 in.2 5. 96 m2 6. 165 mm2 7. 84 m2 8. 52.5 ft2 9. 18 m2 10. a. Each area is 135 ft2. b. Each area is 120 ft2. c. Answers may vary. Sample: Each plan provides the same area for parking spaces and for grass. The rectangular parking-space plan allows cars to enter a space from two directions. 11. Answers may vary. Sample: Laser: 85 ft2; 470: 95 ft2; Soling: 140 ft2; Finn: 100 ft2 12. 48.6 m2 13. 231 in.2 14. 100 mm2 15. a. 189 ft2 b. 5 cases c. $195.80 8-7

  12. 3 5 Areas of Polygons COURSE 3 LESSON 8-7 16. Answers may vary. Sample: 17. 3.5 m 18. a. Answers may vary. Sample: 104,000 km2 b. The actual area is 109,624 km2. 19. The area of a square is larger than the area of a triangle. 20. 1 : 2 21. 22. 65 23. 24.5 24. 30 25. 5 26. 60° 27. 135° 28. 157.5° 29. 165.6° 30. $51.38 8-7

  13. Areas of Polygons COURSE 3 LESSON 8-7 Find the area of each. 1. 2. 3. 12 in.2 10cm 14 cm2 56 ft2 8-7

  14. Grass Seed example 80 ft 96 ft House 35 ft x 45 ft 75 ft 140 ft You want to buy enough grass seed to cover the property around the house above. The grass seed comes in 50 lb bags. One bag will cover 250 square feet. Calculate the total square footage of the yard (add 15% to that number for spillage), the number of bags needed, and the total cost if each bag costs $21.99. (there is sales tax on this)

  15. Circumferences and Areas of Circles Circumference - it is the distance around a circle. To find the circumference we need to know about  (Pi) Pi is the ratio of the circumference divided by the diameter of any circle.  = C  d If C  d= Then the inverse of that would mean: C =  • d

  16. Use the formula for circumference. C = d C = (125) Substitute 125 for d. 125 Use a calculator. 392.6990817 Circumferences and Areas of Circles COURSE 3 LESSON 8-8 The diameter of a tractor tire is 125 cm. Find the circumference. Round to the nearest tenth. The circumference is about 392.7 cm. 8-8

  17. Use the formula for circumference of a circle. C = d = (24) Substitute. 24 Use a calculator. 75.398224 Circumferences and Areas of Circles COURSE 3 LESSON 8-8 The diameter of a small pizza is 24 cm. Find its circumference. Round to the nearest tenth. The circumference of the small pizza is about 75.4 cm. 8-8

  18. Circumference The circumference of the circle to the left is about 47.12 ft. What is the diameter and the radius to the nearest tenth? C =  • d 47.12 =  • d   15 = d 7.5 = r

  19. Circumferences and Areas of Circles Area of a Circle- How do we develop a formula for a circle???? A = b x h =(1/2 •C) x h =(1/2• • D) x h =(1/2•• 2r) x h =(• r) x h Parallelogram Radius =(• r) x r = • r • r = • r2 1/2 circumference

  20. Use the formula for area of a circle. A = r2 = (12)2 Substitute. 12 Use a calculator. 452.38934 Circumferences and Areas of Circles COURSE 3 LESSON 8-8 The diameter of a small pizza is 24 cm. Find its area. Round to the nearest tenth. The radius of the pizza is 24 ÷ 2, or 12 cm. Use the radius to find the area. The area of a small pizza is about 452.4 cm2. 8-8

  21. Substitute 12 for s. A = (12)2 = 144 Simplify. Area of circle = r2 A = (6)2 Substitute 6 for r. Multiply. Round to the nearest tenth. 113.1 Circumferences and Areas of Circles COURSE 3 LESSON 8-8 Find the area of the unshaded region of the square tile with a circle inside of it, as shown below. Round to the nearest tenth. You can separate the figure into a circle and a square. Step 1 Find the area of the square. Area of square = s2 Step 2 Find the area of the circle. Step 3 Subtract the area of the circle from the area of the square. The area of the shaded region is about 144 cm2 – 113.1 cm2 = 30.9 cm2. 8-8

  22. Homework Section 8-8 # 1-11 Odd, 13-18 All

  23. Example 1 foot You work for a company that manufactures lids for tin cans. The sheet that the lids are cut from is shown above. The sheet weighs 2 pounds. The company is paid $0.025 for each 100 lbs or recycled material (the blue). If the company makes 4 billion lids a month, how much money should the expect to recover from the recycled material?

  24. Circumferences and Areas of Circles COURSE 3 LESSON 8-8 Pages 450–452 Exercises 1. 37.7 m 2. 15.7 ft 3. 31.4 cm 4. 28.9 in. 5. 28.3 cm 6. 110.6 mm 7. 201.1 cm2 8. 380.1 in.2 9. 706.9 m2 10. 51.5 yd2 11. 346.4 cm2 12. 32.2 ft2 13. 22.3 ft2 14. 104.9 in.2 15. 1,253.4 ft2 16. 26.6 yd2 17. 4.1 m2 18. 29.9 ft2 19. 66 cm 20. 44 km 21. 22 m 22. 88 in. 23. 66 cm2; subtract the area of the smaller circle from the area of the larger circle. 8-8

  25. Circumferences and Areas of Circles COURSE 3 LESSON 8-8 24. The square, with an area of 4 in.2, has a greater area than the circle, with an area of 3.14 in.2 25. 3.56 cm; 7.11 cm 26. 0.27 in.; 0.54 in. 27. 24.02 ft; 48.05 ft 28. 10.00 m; 20.00 m 29. 315.8 ft2 30. a. 3 : 1 b. 9 : 1 c. a : b; a2 : b2 31. 228 ft2 32. 535.5 ft2 33. 2,946.7 ft2 34. 12 ft 35. a. 192 cm2 b. 33.3% 36. a. about 4.5 cm2 36. (continued) b. 6 h: 0.81 cm2; 7 h: 1.40 cm2; 8 h: 1.26 cm2; less than 6 h: 0.59 cm2; more than 8 h: 0.45 cm2 37. 15 lines 38. C 39. I 40. B 8-8

  26. Circumferences and Areas of Circles COURSE 3 LESSON 8-8 41. [2] Use 70 for 74 and 90 for 84 to avoid rounding in the same direction. Use 40 for 42. Substitute into a formula adding the area of a rectangle to the area of a circle. A = w + r2 = (70)(90) + 3(40)2 = 6,300 + 4,800 = 11,100 m2 [1] minor computational error OR correct answer without explanation 42. 6 times 43. SAS 44. ASA 45. The corresponding angles are congruent. 46. The alternate interior angles are congruent. 8-8

  27. Looking at the trail below, you need to post a 1 mile, 5 mile and 10 mile sign. Decide where each should go. SHOW ALL WORK THAT GOES WITH IT. Example - track 3000 feet 1000 feet 3000 feet Trail starts here

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