https://www.egyigcse.com/forums/ Wed, 27 May 2026 00:41:19 +0000 MyBB https://www.egyigcse.com/forums/thread-155.html Sat, 02 Apr 2011 12:03:39 +0000 7ossam]]> https://www.egyigcse.com/forums/thread-155.html
Help!!! please I have a trail exam tomorrow]]>
Help!!! please I have a trail exam tomorrow]]> https://www.egyigcse.com/forums/thread-120.html Sun, 16 Jan 2011 18:32:23 +0000 Omneya Mostafa]]> https://www.egyigcse.com/forums/thread-120.html First of all u need to know the followin' :
1)perimeter and area of
a rectangle "2x+2y" & "xy"
and triangle "a+b+c" & "(1/2*b*hypo) or (1/2*b*c*sinA)"
, the circumference and area of a circle "2πr" & "πr^2"
, the area of a parallelogram "base*height"
and a trapezium "{(base1+base2)/2}*height"
, the volume of a cuboid "xyz"
, prism "base area*length"
and cylinder "πr^2h"
and the surface area of a cuboid "2xy+2yz+2xz"
and a cylinder "2πrh".
2) Solve problems involving the arc length "(2πr)*α/360"
and sector area "(πr^2)*α/360" as fractions of the circumference and area of a circle,
the surface area and volume of a sphere, pyramid and cone (given formulae for the sphere, pyramid and cone).
This is all what you need to know about mensuration as explanation. The tricks comes with the questions so dun hesitate to ask any. But be sure that if u got the idea of the chapter all questions will be more that easy 4 ya to answer
hope I helped --------------------------------------------------------------------------------]]> First of all u need to know the followin' :
1)perimeter and area of
a rectangle "2x+2y" & "xy"
and triangle "a+b+c" & "(1/2*b*hypo) or (1/2*b*c*sinA)"
, the circumference and area of a circle "2πr" & "πr^2"
, the area of a parallelogram "base*height"
and a trapezium "{(base1+base2)/2}*height"
, the volume of a cuboid "xyz"
, prism "base area*length"
and cylinder "πr^2h"
and the surface area of a cuboid "2xy+2yz+2xz"
and a cylinder "2πrh".
2) Solve problems involving the arc length "(2πr)*α/360"
and sector area "(πr^2)*α/360" as fractions of the circumference and area of a circle,
the surface area and volume of a sphere, pyramid and cone (given formulae for the sphere, pyramid and cone).
This is all what you need to know about mensuration as explanation. The tricks comes with the questions so dun hesitate to ask any. But be sure that if u got the idea of the chapter all questions will be more that easy 4 ya to answer
hope I helped --------------------------------------------------------------------------------]]> https://www.egyigcse.com/forums/thread-14.html Mon, 19 Jul 2010 22:10:26 +0000 Hassab ™]]> https://www.egyigcse.com/forums/thread-14.html Powers and Roots

A power tells you to multiply a number by itself.

For example, 5^3 means 5 x 5 x 5 which is 125.

2^4 means 2 x 2 x 2 x 2 which is 16.

It is a short way of writing out calculations.

For example, 3^3 x 4^2 = 3 x 3 x 3 x 4 x 4 = 432

A root is the opposite of a power.



- means 'what number do you square to get 4?'


The answer is 2.


- means 'what number do you cube (multiply by itself 3 times) to get 27?'

The answer is 3.


Rules of indices

There are several rules that you will need to know.

Rule 1

When you multiply indices of the same number you add the powers.

For example: 5^4 x 5^3 = 5^4 + 3 = 5^7

Rule 2

When you divide indices of the same number you subtract the powers.


Rule 3

Indices outside a bracket multiply.

For example: (3^2) ^4 = 3^2 x 4 = 3^8

Rule 4

Negative indices mean reciprocal, i.e. 'one over...' or 'put on the bottom of a fraction'.


Rule 5

When the power is a fraction the top of the fraction (numerator) is a power and the bottom of the fraction is a root.


Rule 6

Anything to a power of 1 is just itself and we normally don't bother putting the 1 there i.e. 5^1 is just 5.

Anything to a power of 0 is equal to 1, it doesn't matter what number it is!

i.e. 10^0 = 1, 2^0 = 1, x^0 = 1, etc.

There you go! There's your rules. Now practice using them by doing some questions!


The rules of Indices also work in Algebra (after all the letters or variables represent numbers anyway!).

So with algebraic fractions you can take the powers at the bottom from the powers at the top and simplify the expression (a bit like cancelling the powers on the top and bottom of the fraction).[/size]]]> Powers and Roots

A power tells you to multiply a number by itself.

For example, 5^3 means 5 x 5 x 5 which is 125.

2^4 means 2 x 2 x 2 x 2 which is 16.

It is a short way of writing out calculations.

For example, 3^3 x 4^2 = 3 x 3 x 3 x 4 x 4 = 432

A root is the opposite of a power.



- means 'what number do you square to get 4?'


The answer is 2.


- means 'what number do you cube (multiply by itself 3 times) to get 27?'

The answer is 3.


Rules of indices

There are several rules that you will need to know.

Rule 1

When you multiply indices of the same number you add the powers.

For example: 5^4 x 5^3 = 5^4 + 3 = 5^7

Rule 2

When you divide indices of the same number you subtract the powers.


Rule 3

Indices outside a bracket multiply.

For example: (3^2) ^4 = 3^2 x 4 = 3^8

Rule 4

Negative indices mean reciprocal, i.e. 'one over...' or 'put on the bottom of a fraction'.


Rule 5

When the power is a fraction the top of the fraction (numerator) is a power and the bottom of the fraction is a root.


Rule 6

Anything to a power of 1 is just itself and we normally don't bother putting the 1 there i.e. 5^1 is just 5.

Anything to a power of 0 is equal to 1, it doesn't matter what number it is!

i.e. 10^0 = 1, 2^0 = 1, x^0 = 1, etc.

There you go! There's your rules. Now practice using them by doing some questions!


The rules of Indices also work in Algebra (after all the letters or variables represent numbers anyway!).

So with algebraic fractions you can take the powers at the bottom from the powers at the top and simplify the expression (a bit like cancelling the powers on the top and bottom of the fraction).[/size]]]>