GRADE: 9
SUBJECT: MATHEMATICS
TERM FOUR
FORMAL ASSESSMENT TASK - INVESTIGATION
Name: _______________________________________________________
Class: ___________________________ Date: ______________________
School: __________________________ Teacher:___________________
FAT
Activity/Form
4.1
INVESTIGATION
TOTAL
Learner’s
mark
Learner’s %
1
1
MATHEMATICS GRADE 9 FORMAL ASSESSMENT TASK (FAT) 4.1:
INVESTIGATION - Geometry of 3D objects
Total: 60 Marks
Time: 1 period in the class
Name: _____________________________________
Date: _____________
____________________________________________________________________________________________
Instructions:
1) Write your name and date in the spaces provided.
2) Show calculations as requested on question paper.
3) You may use a calculator.
4) It must be your own work.
5) Check your answers.
Question 1: Match the definitions to the correct term in the Object – column. Write only the letter ( from the
definition column) in the blank column.
2
Object
Regular
polygon
Platonic solid
3
Polyhedron
4
Face
5
Edge
C) A 3D solid that consists of a polygon as a base and all the side faces meet
at a single vertex.
D) A shape where all sides are of equal length and all angles are equal in
size
E) Two faces meet in a straight line segment
6
Vertices
F) A solid in which every face is a polygon
7
Pyramid
G) The flat plane surface on a polyhedron
8
Cylinder
H) A solid in which all faces are regular polygons and the same number of
faces meet at each vertex.
9
Sphere
I) A corner where a number of edges and faces meet
1
Answer
Definition
A) A perfectly rounded solid in three dimensional space
B) Identical circular ends that are flat and parallel to each other
[9]
Mathematics Grade 9
2
Question 2: Platonic Solids :
Facts: There are only five geometric solids that can be made using a regular polygon and having the same number
of these polygons meet at each corner.
2.1 Complete the table by writing the correct answer to the letters ( a – s).
Platonic Solid
Picture
(17)
Number Number Number
Number
of Faces
of
of
Unfolded
of Faces Shape of Faces
at each Vertices Edges Polyhedron (Net)
(F)
Vertex
(V)
(E)
Tetrahedron
4
Equilateral
Triangle
(3-sided)
Cube
a
e
3
l
o
Octahedron
b
f
4
m
p
Dodecahedron
c
g
j
n
q
Icosahedron
d
h
k
12
Mathematics Grade 9
i
4
6
30
3
2.2 Euler's formula:V – E + F = 2, where V = number of vertices; E = number of edges; F = number of faces:
Use the general formula to check your answer at the Icosahedron
(3)
[20]
Question 3: Match the correct net with the correct 3D object. Only write the letter of the net next to the object.
M atc
A
___
____
B
____
C
____
D
____
E
___
F
[6]
Mathematics Grade 9
4
Question 4:
Calculate the volume of the cylinder with a height of 2m and a radius of 1,5m.
[3]
Question 5:
Complete the table using your knowledge of real life objects:
Object
1
Block of margarine
2
A dice
3
Tin of paint
4
Marble
Name of solid
Number of faces
Number of
vertices
Number of edges
[16]
Question 6: Draw the net of a square pyramid
Mathematics Grade 9
[2]
5
Question 7:
Sally has drawn an incomplete net for the 3D object shown.
a)
Copy her incomplete net four times and show four different ways that she could
complete it.
Mathematics Grade 9
[4]