Home' Trinidad and Tobago Guardian : July 5th 2017 Contents SEA B1
Wednesday, July 5, 2017 guardian.co.tt
TUTORIAL: SYMMETRY, DATA
A line of symmetry is a line that divides a figure into two congruent halves
that are mirror images of each other.
A figure with a line of symmetry is said to be symmetrical.
A way to tell whether a figure has a line of symmetry is to fold along a
line so that the two folded parts match exactly.
The fold line is called a line of symmetry.
A figure is symmetric if it can be folded so that both sides match.
A figure may have more than one line of symmetry.
Each line of symmetry in a figure divides the figure into two congruent
A line of symmetry is used to show the reflection symmetry of a point, a
line or a shape.
A line of symmetry can also separate a shape into two parts, where one
part is a reflection of the other.
A rectangle has 2 lines of .
A square has 4 lines of
A circle has an infinite
Some figures have
number of lines of symmetry
no line of symmetry.
There are many examples of symmetry in our environment, look for them.
Symmetry results in balance.
Whenever a shape is moved, a transformation takes place. The shape
does not change but the position of the shape changes.
We can flip a shape or figure across a line of symmetry or a mirror line.
This is called a reflection.
The reflection of a point is another point on the other side of a line of
symmetry. Both the point and its reflection are the same distance from
If a shape is reflected, the image of each point will be the same distance
from the line of symmetry on the opposite side.
EXAMPLE: Complete the shape so that the line XY is the line of symmetry.
(i) Collecting Data (surveys, samples, compiling data)
Surveys - Have you ever been asked questions about naming your favourite
colour or fruit or pet?
These types of questions are often asked when someone is conducting
A survey is a method of collecting statistical data in which people are
asked to answer questions.
The entire group of people or objects studied by a statistician is called a
Usually a small group of people or objects are chosen to represent the
population, this part of the population is called a SAMPLE.
There are 400 students in a school. 80 students were chosen at random
and asked what their favourite subject is in school.
400 is the POPULATION and 80 is the SAMPLE.
RANDOM SAMPLES -
In a random sample, each person in the population has an equal chance
of being included.
To pick a random sample of students from the population of 400, the
names of all the students were written on pieces of paper and put into a
80 names were then chosen from the bag.
(ii) COMPILING DATA
Once data has been collected it can be complied using tally marks in a table
to tally the answers
Depending on the amount in the sample, you may need to use tallies to get an
accurate amount. In a tally, the fifth item is shown as a diagonal stroke across the
previous four strokes. Tally marks are used to record the frequency of the data.
A frequency table is used to record and summarize data.
The frequency is the number of times something occurs.
Tally marks record the frequency of the data.
Use tally marks and make a frequency table to show how many words in
the sentence below have 1 letter, 2 letters, 3 letters and so on.
Mary had a little lamb its fleece was white as snow.
The total of the frequency must be the same as the number of words in
(iii) Interpretation of data on tables/charts.
The branch of mathematics called statistics deals with presenting and
interpreting numerical data. Data can be shown on a frequency table like
the one below.
The data shows the number of children per family in 50 families.
Use the data in the sample to answer the following:
1. What fraction of the sample families have 2 children per family?
Answer: 15/50 = 3/10
2. Predict the number of families out of 200 that have 1 child?
Answer: for 50 families the number is 9 families
For 200 (= 50 x 4) families the number will be 9 x 4 = 36 families
SEA PRACTICE TEST SERIES 2016 -- 2017
SEA PRACTICE TEST 8 WITH TUTORIALS (MAY - JULY 2017)
Each question is worth 1 mark.
Answer ALL questions.
Show ALL working in the Working Column.
1. Write 9.82 to the NEAREST TENTH.
2.5 x 0.03
4. Express 5 2/3 as an IMPROPER fraction.
5. David gave Brandon 5/9 of his DVD movies. What FRACTION
of his DVD movies does David have left?
Continued on the next page
Links Archive July 4th 2017 July 6th 2017 Navigation Previous Page Next Page