A bar chart where each category has two bars instead of one. This is used when two frequencies exist for a category. This type of graph allows for comparisons to be made between the two sets of values.
Category Archives: D
Describe
Use words to explain what has happened.
Example: Describe, as a column vector, the translation of A to B.

πKey Topics: Reflection, Rotations, Translations, Enlargements
πAlso Look up: Describe Fully, Reflect, Rotate, Translate, Enlarge
Describe fully
A command word that, when used in transformation questions is asking for:
If it is a reflection: A reflection in the line….(and then the equation of the mirror line)
If it is a translation: A translation by the vector…. (giving the vector). You may also say ‘A translation by ___ to the right and ___ up’.
If a rotation: A rotation _______(give clockwise/ anticlockwise) by _____(give the angle) about the centre _____ (give the coordinate of the centre).
In an enlargement: An enlargement of scale factor ____(give the scale factor) about the centre ___(give the centre of enlargement).
Diameter
The distance between two points on the circumference of a circle, passing through the centre. It is equivalent to 2 lots of the radius.
Example:

π Key Diameter Topics: Parts of a Circle, Area of a Circle, Circumference of a Circle, Circle Theorems
πAlso Look Up: Circle, Radius, Sector
Double
Divisor
Divisible
Directed Number
A number that has a positive or a negative sign at the front of it.
Example: –2 or +7
π Key Directed Number Topics: Ordering Negatives, Negative Addition/Subtraction, Negative Multiplication and Division
Direct Proportion
Where two values are linked by a common multiple. The key feature is that when you have none of one, you have none of the other.
Example: x and y are in direct proportion.Β
π Key Direct Proportion Topics: Direct and Inverse Proportion
Difference
Another way of asking you to subtract two numbers.Β
Example: Find the difference of 8 and 17.Β
π Key Difference Topics: Subtraction, Negative Numbers