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Form 1 Mathematics Chapter 10. Lesson requirement Textbook 1B Workbook 1B Notebook Before lessons start Desks in good order! No rubbish

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 Missing HW  Detention  Ch 10 SHW(I)  28 May (Tue)  Ch 10 SHW(II)  31 May (Fri)  Ch 10 SHW(III)  31 May (Fri)  Ch 10 OBQ  31 May (Fri)  Ch 10 CBQ  4 June (Tue)

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Form 1 Mathematics Chapter 10 Lesson requirement Textbook 1B Workbook 1B Notebook Before lessons start Desks in good order! No rubbish around! No toilets! Keep your folder at home Prepare for Final Exam Missing HW Detention Ch 10 SHW(I) 28 May (Tue) Ch 10 SHW(II) 31 May (Fri) Ch 10 SHW(III) 31 May (Fri) Ch 10 OBQ 31 May (Fri) Ch 10 CBQ 4 June (Tue) The sum of the interior angles of any triangle is 180. i.e.In the figure, a + b + c = 180 . [Reference: sum of ] The sum of angles at a point is 360 . e.g. In the figure, a + b + c + d = 360. [Reference: s at a pt.] The sum of adjacent angles on a straight line is 180 . e.g. In the figure, a + b + c = 180. [Reference: adj. s on st. line] When two straight lines intersect, the vertically opposite angles formed are equal. i.e. In the figure, a = b. [Reference: vert. opp. s] The corresponding angles formed by parallel lines and a transversal are equal. i.e. In the figure, if AB // CD, then a = b. [Reference: corr. s, AB // CD] The alternate angles formed by parallel lines and a transversal are equal. i.e. In the figure, if AB // CD, then a = b. [Reference: alt. s, AB // CD] The sum of the interior angles of parallel lines on the same side of the transversal is 180 . i.e. In the figure, if AB // CD, then a + b = 180. [Reference: int. s, AB // CD] Example 6: p q r In the figure, AB, QR and CD are parallel lines, while PQ and RS are another pair of parallel lines. If RSA = 66, find QPD. Using the notation in the figure, r + 66 = 180 (int. s, AD // QR) r = 114 q = r (alt. s, PQ // RS) q = 114 p + q = 180 (int. s, QR // CD) p + 114 = 180 p = 66 QPD = 66 Example 7: Find the unknown angle x in the figure. Draw the straight line AT such that AT // PQ. Since PQ // NS, we have AT // NS. Using the notation in the figure, y = 180 (int. s, PQ // AT) y = 35 67 + x + y = 180 (int. s, NS // AT) 67 + x + 35 = 180 x = 78 A y Pages 154 155 of Textbook 1B Questions 4 25 Pages 59 61 of Workbook 1B Question 1 - 8 The conditions needed for two lines to be parallel: 1. If the corresponding angles formed by two lines and a transversal are equal, then the two lines are parallel. i.e.In the figure, if a = b, then AB // CD. [Reference: corr. s equal] The conditions needed for two lines to be parallel: 2. If two lines are cut by a transversal and the alternate angles are equal, then the two lines are parallel. i.e.In the figure, if a = b, then AB // CD. [Reference: alt. s equal] The conditions needed for two lines to be parallel: 3. If two lines are cut by a transversal and the interior angles on the same side of the transversal are supplementary, then the two lines are parallel. i.e.In the figure, if a + b = 180, then AB // CD. [Reference: int. s supp.] Example 1: Are the lines AB and CD in the figure parallel to each other? BFG = DGH = 75 AB // CD ( corr. s equal ) Example 2: Determine if lines AC and DF as shown in the figure are parallel. ABE = FEB = 125 AC // DF (alt. s equal) Example 3: Determine if lines AB and DC as shown in the figure are parallel. ABC + DCB AB // DC (int. s supp.) = 150 + 30 = 180 Example 4: Determine if lines DE and FG as shown in the figure are parallel. FCB + 35 + 50 = 180 (adj. s on st. line) FCB = 180 35 50 = 95 DBA = FCB = 95 DE // FG (corr. s equal) Example 5: In the figure, AB // CD, ABC = 40 , BCD = 2p, CDE = 3p 20. (a) Find p. (b) Is it true that BC // DE? Give reasons. (a) 2p = 40 (alt. s, AB // CD) p = 20 (b) BCD = 2p = 40 CDE = 3p 20 = 3 20 20 = 40 BCD = CDE = 40 BC // DE (alt. s equal) Missing HW Detention Ch 10 SHW(I) 28 May (Tue) Ch 10 SHW(II) 31 May (Fri) Ch 10 SHW(III) 31 May (Fri) Ch 10 OBQ 31 May (Fri) Ch 10 CBQ 4 June (Tue) Enjoy the world of Mathematics! Ronald HUI