Form 1 Mathematics
Chapter 6
SHW (III), Re-dictation & OBQ
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Today
SHW (I), Dictation, Re-dictation Correction
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1 Feb (Fri)
SHW (II), (III), Drawing, OBQ Correction,
Bring Textbook, Workbook 1B
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4 Feb (Mon)
CBQ
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6 Feb (Wed)
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Here are the answers:
1. 線段
Line Segment
2. 頂點
Vertex
3. 平行線
Parallel Lines
4. 垂直線
Perpendicular Lines
5. 鈍角
Obtuse Angle
6. 等腰三角形 Isosceles Triangle
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Next we have:
7. 圓周
8. 直徑
9. 對角線
10. 正多邊形
11. 等邊五邊形
12. 等角六邊形
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Correction: 10 times
Circumference
Diameter
Diagonal
Regular Polygon
Equilateral Pentagon
Equiangular Hexagon
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Give the English name of the followings:
1. 銳角
2. 反角
3. 平面圖形
4. 曲面
5. 半徑
6. 相交
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Give the English name of the followings:
7. 四邊形
8. 多面體
9. 等距畫圖
10. 均勻橫切面
11. 等邊三角形
12. 全等八角形
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Can you get them all?
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Here are the answers:
1. 銳角
Acute angle
2. 反角
Reflex angle
3. 平面圖形
Plane figure
4. 曲面
Curved surface
5. 半徑
Radius
6. 相交
Intersect
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Next we have:
7. 四邊形
8. 多面體
9. 等距畫圖
10. 均勻橫切面
11. 等邊三角形
12. 全等八角形
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Can you get them all?
Quadrilateral
Polyhedron / Polyhedra
Isometric drawing
Uniform cross-section
Equilateral triangle
Regular octagon
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Points 點
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Lines 線
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Planes 面
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Angles:
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Name of angles (middle letter is vertex!)
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There are six types:
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When two lines in the same plane, but they
do not intersect each other, they are called
parallel lines (平行線)
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A pair of parallel lines
is denoted by
a pair of arrows
(箭號)
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We write “AB // CD”
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When two lines in the same plane are
intersecting at right angle (90), they are
called perpendicular lines (垂直線)
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A right angle will
be clearly shown
in a pair of
perpendicular lines
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We write “AB  CD”
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Any shape enclosed by line segments in the
same plane is called Plane Figure.
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Otherwise, it should be a curved surface.
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The name of the polygons depends on the
number of straight lines:
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Triangle
Quadrilateral
Pentagon
Hexagon
Octagon
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Number prefix (from wikipedia)
3 lines
4 lines
5 lines
6 lines
8 lines
(Tri-)
(Quadri-)
(Penta-)
(Hexa-)
(Octa-)
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Diagonal (對角線) is the line segment
joining any two non-adjacent (不相鄰)
vertices (頂點 vertex)
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A line segment joining two adjacent vertices
is called a side (邊)
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Same side  Equilateral (等邊) polygon
Same angle  Equiangular (等角) polygon
Both
 Regular polygon (正多邊形)
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All points on the circle (circumference 圓周)
are at the same distance (radius半徑) from
the a fixed point (centre 圓心).
Diameter (直徑) is
2 x Radius (d = 2r)
C = d x  (圓周率)
or C = 2r
  3.14159 26535 897…
C
d
r
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Triangles are formed by three straight lines
Its name depends on its angles
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Sum of angles of a triangle is 180
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a + b + c = 180
(Straight angle = 180)
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 Sum of : a + b + c = 180
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 Sum of : a + b + c = 180
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Solids are 3-D (three-dimensional) figures.
Vertex
Plane
Edge
Curved
surface
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Dotted lines
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Isometric Drawing
1 cm
1 cm
1 cm
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If we cut a solid at right angle to its length,
the plane is called a cross-section.
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If planes from the parallel cuts are the same,
the plane is a uniform cross-section
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When all faces of a solid are polygons only, it
is called a polyhedron.
Yes!
No!
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The connected planes of a polyhedron are
called a net.
Drawing Exercises & Dictation
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Today!!!!
SHW (III) & OBQ
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30 Jan (Wed)
SHW (I), (II), Dictation Correction
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1 Feb (Fri)
SHW (III), OBQ Correction
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4 Feb (Mon)
CBQ
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6 Feb (Wed)
Enjoy the world of Mathematics!
Ronald HUI