Form 1 MathematicsChapter 6

SHW (III), Re-dictation & OBQ Today

SHW (I), Dictation, Re-dictation Correction

1 Feb (Fri) SHW (II), (III), Drawing, OBQ

Correction, Bring Textbook, Workbook 1B

4 Feb (Mon) CBQ

6 Feb (Wed)

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

Next we have: 7. 圓周 Circumference 8. 直徑 Diameter 9. 對角線 Diagonal 10. 正多邊形 Regular Polygon 11. 等邊五邊形 Equilateral

Pentagon 12. 等角六邊形 Equiangular

Hexagon

Correction: 10 times

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

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

Can you get them all?

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

Next we have: 7. 四邊形 Quadrilateral 8. 多面體 Polyhedron / Polyhedra 9. 等距畫圖 Isometric drawing 10. 均勻橫切面 Uniform cross-section 11. 等邊三角形 Equilateral triangle 12. 全等八角形 Regular octagon

Can you get them all?

Points 點

Lines 線

Planes 面

Angles:

Name of angles (middle letter is vertex!)

There are six types:

When two lines in the same plane, but they do not intersect each other, they are called parallel lines ( 平行線 )

A pair of parallel lines is denoted by a pair of arrows ( 箭號 )

We write “AB // CD”

When two lines in the same plane are intersecting at right angle (90), they are called perpendicular lines ( 垂直線 )

A right angle willbe clearly shownin a pair of perpendicular lines

We write “AB CD”

Any shape enclosed by line segments in the same plane is called Plane Figure.

Otherwise, it should be a curved surface.

The name of the polygons depends on the number of straight lines:

Triangle 3 lines (Tri-) Quadrilateral 4 lines (Quadri-) Pentagon 5 lines (Penta-) Hexagon 6 lines (Hexa-) Octagon 8 lines (Octa-)

Number prefix (from wikipedia)

Diagonal ( 對角線 ) is the line segment joining any two non-adjacent ( 不相鄰 ) vertices ( 頂點 vertex)

A line segment joining two adjacent vertices is called a side ( 邊 )

Same side Equilateral ( 等邊 ) polygon Same angle Equiangular ( 等角 )

polygon Both Regular polygon ( 正多邊形 )

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 = 2r

3.14159 26535 897…

r

C

d

Triangles are formed by three straight lines

Its name depends on its angles

Sum of angles of a triangle is 180

a + b + c = 180 (Straight angle = 180)

Sum of : a + b + c = 180

Sum of : a + b + c = 180

Solids are 3-D (three-dimensional) figures.

PlaneVertex

Edge

Curved surface

Dotted lines

Isometric Drawing

1 cm 1 cm

1 cm

If we cut a solid at right angle to its length, the plane is called a cross-section.

If planes from the parallel cuts are the same, the plane is a uniform cross-section

When all faces of a solid are polygons only, it is called a polyhedron.

Yes! No!

The connected planes of a polyhedron are called a net.

Drawing Exercises & Dictation Today!!!!

SHW (III) & OBQ 30 Jan (Wed)

SHW (I), (II), Dictation Correction 1 Feb (Fri)

SHW (III), OBQ Correction 4 Feb (Mon)

CBQ 6 Feb (Wed)

Enjoy the world of Mathematics!

Ronald HUI