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Chapter 8 Introduction to Geometry
Chapter 8
Form 1 Mathematics
Introduction to Geometry
F.1 ( )_______________________( )
Worksheet 2
1.
In the spaces below, draw
(a) an acute-angled triangle,
(b) a right-angled triangle. (c) an obtuse-angled triangle.
P
D
A
2.
C
E
B
Q
F
R
In the above figures,
 ABC is a ____________________ triangle,
 DEF is an ____________________ triangle,
 PQR is an ____________________ triangle.
The sum of the three angles of a triangle is _______________.
3.
A
B
Figure (a)
Figure (b)
Figure (c)
In the above,
Figure (a) shows a quadrilateral,
Figure (b) shows a polygon with 5 sides which is called a
polygon with 6 sides which is called a
The line segment AB is a
and Figure (c) shows a
.
of the polygon. Draw another diagonal in Figure (c).
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Chapter 8 Introduction to Geometry
Form 1 Mathematics
4.
Figure (a)
Figure (b)
Figure (c)
In Figure (a), the polygon with all sides equal is called an
polygon.
In Figure (b), the polygon with all angles equal is called an
polygon.
In Figure (c), the polygon with all sides and all angles equal is called a
5.
3-D stands for
.
6.
In the figure, the object that occupies space is called a
The surface of the figure is called a
.
The line segment AB in the figure is an
A and B are the
7.
.
.
of the object.
If the object shown on the right is cut along its length by the
plane, then the figure obtained is called a
.
Draw the cross-section when the solid is cut along the plane ABCD.
A
B
C
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polygon.
Chapter 8 Introduction to Geometry
8.
Form 1 Mathematics
If the cross-sections that we obtain from a solid are all the same, then the cross-sections are
called
9.
.
In the figure, the surfaces of the objects are all
polygons.
These objects are called
10. The figure below shows some
.
which can be folded to form a 3-D figure.
Try to draw the 3-D figures in the spaces below.
Which ones are polyhedron? Why?
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Chapter 8 Introduction to Geometry
Exercise:
Form 1 Mathematics
B
A
G
F
C
D
E
Refer to the polygon above.
The polygon ABCDEF is a ___________________________________.
The polygon AGEF is a ______________________________________.
 AFG is a __________________ triangle as AF = FG = GA.
Draw a diagonal from C to E.
 CDE is an ____________________ triangle as CD = DE ≠ CE.
It is also an _____________________ triangle as ∠CDE is greater than 90°.
 CEF is a ____________________ triangle as CE ≠ EF ≠ FC.
Challenging question.
Can you find ∠FAB ?
P. 4
Chapter 8 Introduction to Geometry
Form 1 Mathematics
Glossary
diagonal
face
acute-angled triangle
vertex / vertices
right-angled triangle
cross-section
obtuse-angled
triangle
uniform
cross-section
polyhedron /
polyhedra
scalene triangle
isosceles triangle
net
equilateral triangle
quadrilateral
pentagon
hexagon
equilateral polygon
equiangular polygon
regular polygon
three dimensional
figure
solid
edge
P. 5