What is the equation to work out the Circumference of a Circle? 

Circumference = (Pie) X Diameter *C=Pd* 
 
What is the equation to work out the Area of a Circle? 

Area = (Pie) X r *Radius * X r *Radius* *A=Prr* or r2 *squared* 
 
What is the equation to work out the Rea of a Trapezium? 

a + b / 2 x height *a is the length of the top line, b is the bottom line* 
 
What is the equation to work out the Rea of a Triangle? 

b x h / 2 *base times height divided by two* 
 