|
| 1 | +# Pi = 3.2? |
| 2 | + |
| 3 | +<div class="dictionary"> |
| 4 | + |
| 5 | +__Noun__: Parallelogram |
| 6 | +__Pronunciation__: /ˌparəˈlɛləɡram/ |
| 7 | + |
| 8 | +1. a portmanteau word combining parallel and telegram. A message sent each |
| 9 | +week by the Parallel Project to bright young mathematicians. |
| 10 | + |
| 11 | +</div> |
| 12 | + |
| 13 | +* Tackle each Parallelogram in one go. Don’t get distracted. |
| 14 | +* Finish by midnight on Sunday if your whole class is doing parallelograms. |
| 15 | +* Your score & answer sheet will appear immediately after you hit SUBMIT. |
| 16 | +* Don’t worry if you score less than 50%, because it means you will learn something new when you __check the solutions__. |
| 17 | + |
| 18 | + |
| 19 | +## 1. How big is a slice of Pi? |
| 20 | + |
| 21 | +We all love pi, but it has a lot of digits! |
| 22 | + |
| 23 | +Wouldn’t life be simpler if we just rounded it a little? Made it a bit more bite size? |
| 24 | + |
| 25 | +Watch this video about the narrowly averted disaster, when pi almost officially became 3.2. |
| 26 | + |
| 27 | +Luckily there was a mathematician passing by! |
| 28 | + |
| 29 | +@[youtube](bFNjA9LOPsg?rel=0) _(If you have problems watching the video, right click to open it in a new window)_ |
| 30 | + |
| 31 | +::: problem id=1_1 marks=1 |
| 32 | +__1.1__ Which state almost mistakenly legislated that pi was in fact equal to 3.2? |
| 33 | + |
| 34 | +* [ ] Alaska |
| 35 | +* [x] Indiana |
| 36 | +* [ ] Washington |
| 37 | +* [ ] New York |
| 38 | +{.col-5} |
| 39 | +::: |
| 40 | + |
| 41 | +::: problem id=1_2 marks=1 |
| 42 | +__1.2__ Which classical problem was Edward Goodwin attempting to solve? |
| 43 | + |
| 44 | +* [x] Squaring the Circle |
| 45 | +* [ ] Proof of the RiemannReimann Hypothesis |
| 46 | +* [ ] The Mutilated Chess Board Problem |
| 47 | +* [ ] The Seven Bridges of Konnigsberg |
| 48 | +::: |
| 49 | + |
| 50 | +::: problem id=1_3 marks=2 |
| 51 | +__1.3__ Which of these numbers, when rounded to 1 decimal place, would give 3.2? |
| 52 | + |
| 53 | +* [ ] 3.94 |
| 54 | +* [ ] 3.14999 |
| 55 | +* [ ] 3.141 |
| 56 | +* [x] 3.15 |
| 57 | +{.col-5} |
| 58 | +::: |
| 59 | + |
| 60 | +::: problem id=1_4 marks=2 |
| 61 | +__1.4__ It may not be possible to construct a square with the same area as a circle, but can you find a square with the same area as this triangle? |
| 62 | + |
| 63 | +What would it’s edge length be? |
| 64 | + |
| 65 | +{image align="center"} |
| 66 | + |
| 67 | +<input type="number" solution="6"/> cm |
| 68 | +::: |
| 69 | + |
| 70 | + |
| 71 | +## 2. Triangle tangle puzzle |
| 72 | +<!--- 2015 () ---> |
| 73 | + |
| 74 | +::: problem id=2_1 marks=3 |
| 75 | +__2.1__ Six identical right-angled triangles fit inside a rectangle as shown in the diagram. |
| 76 | + |
| 77 | +The rectangle measures 24cm by 29cm. |
| 78 | + |
| 79 | +What is the total shaded area in cm<sup>2</sup>? |
| 80 | + |
| 81 | +{image align="center"} |
| 82 | + |
| 83 | +[x] 180 cm<sup>2</sup> |
| 84 | +[ ] 348 cm<sup>2</sup> |
| 85 | +[ ] 30 cm<sup>2</sup> |
| 86 | +[ ] 72 cm<sup>2</sup> |
| 87 | +{.col-4} |
| 88 | + |
| 89 | +^^^ hint id=2_1_1 marks=1 |
| 90 | +It looks like the rectangle has the same height as two of the triangles. |
| 91 | + |
| 92 | +Can you find the height of the triangles by splitting up the shorter length of 24? |
| 93 | + |
| 94 | +{image align="center"} |
| 95 | +^^^ |
| 96 | + |
| 97 | +^^^ hint id=2_1_2 marks=1 |
| 98 | +It looks like the longer length of the rectangle is made of two long triangle sides (which we just found) and a bit left over. |
| 99 | + |
| 100 | +Can we use this to find the shorter side of the triangle? |
| 101 | + |
| 102 | +{image align="center"} |
| 103 | +^^^ |
| 104 | + |
| 105 | +^^^ hint id=2_1_3 marks=1 |
| 106 | +Now knowing that the area of a triangle can be calculated by using 1/2 × base × height. |
| 107 | + |
| 108 | +Find the total area for __all__ 6 triangles. |
| 109 | +^^^ |
| 110 | + |
| 111 | +--- |
| 112 | + |
| 113 | +`6 × (0.5 × 12 × 5) = 180`cm<sup>2</sup> |
| 114 | +::: |
| 115 | + |
| 116 | + |
| 117 | +Before you hit the SUBMIT button, here are some quick reminders: |
| 118 | + |
| 119 | +* You will receive your score immediately, and collect your reward points. |
| 120 | +* You might earn a new badge... if not, then maybe next week. |
| 121 | +* Make sure you go through the solution sheet – it is massively important. |
| 122 | +* A score of less than 50% is ok – it means you can learn lots from your mistakes. |
| 123 | +* The next Parallelogram is next week, at 3pm on Thursday. |
| 124 | +* Finally, if you missed any earlier Parallelograms, make sure you go back and complete them. You can still earn reward points and badges by completing missed Parallelograms. |
| 125 | + |
| 126 | +Cheerio, |
| 127 | +Simon and Ayliean. |
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