Grade 9 Mathematics Guide

,Grade 9 Math
Unit 1: Square Roots and Surface Area.

Review from Grade 8: Perfect Squares

What is a perfect square?

► Perfect square numbers are formed when we multiply a number
(factor) by itself, or square a number.

For Example:

9 is a perfect square, and 3 is it’s factor.


There are other ways to ask the same question....

► What is the square of 3? Meaning what is , or what is =9

► What is 3 squared ? Meaning what is , or what is =9

► What is 3 to the power of 2 ?Meaning what is , or what is =9

We can sketch a diagram of perfect squares, by actually drawing squares.
The factors ( the number that multiplies by itself ) are the side length of the
square and the area of the square is the perfect square number.

Length Length = Area of a Square
( Length )2 = Area




Length Length Area

, 3


and there are 9 little squares
3




The List of Perfect Squares from 1 to 20.
1
1

2

2

. . . etc




These are the perfect
square numbers.

, Review from Grade 8: Square Root

When we multiply a number by itself we find the perfect square




Finding the square root of a number is doing the opposite. We are given
the perfect square and asked to find what number multiplied by itself to get
that number.

Finding the perfect square and finding the square root are called inverse
operations. ( they are opposites ).

The symbol for square root is




Ask yourself....what
number multiplies by
What is ?
itself to equal 49?