# Maths GCSE

Overview of the Trangle part of the course.

HideShow resource information

## Congruence

If one or more of these 4 conditions hold then the two triangles are congruent:

1. SSS - three sides are the same

2. AAS - two angles and a side match up

3. SAS - two sides and an angle match up

4. RHS - a right angle, the hypotenuse and one other side match up

1 of 8

## Scale Factor

For scale factor 'n' :

The sides are n times bigger

The areas are n squared times bigger

The volumes are n cubed times bigger

2 of 8

## Example

2 spheres have surface areas of 16m squared and 25m squared. Find the ratio of their volumes.

Area = a squared : b squared = 16 : 25

Therefore...  a : b = 4 : 5

Therefore...  a cubed : b cubed = 64 :125

Volume of the spheres = 64m cubed and 125m cubed

3 of 8

## Transformations

How to remember the 4 transformations

'TERRY'

T = Translation

E = Enlargement

R = Rotation

R = Reflection

Y

4 of 8

## Translation

When an object is translated all that changes is the position of the object.

You must specify the vector of the translation.

5 of 8

## Enlargement

When an object is enlarged all that changes is the size (unless it is a negative scale factor because then the orientation changes also)

You must specify the scale factor and the centre of enlargement.

6 of 8

## Rotation

When an object is rotated all that changes is the position and orientation.

You must specify the angle turned, the direction turned and the centre of rotation.

7 of 8

## Reflection

When an object is reflected all that changes is the position and orientation.

You must specify the mirror line

8 of 8