Area
Area of a triangle
A=1/2bh
4 sides shape
Square
90 degrees
Right angle
Set of two straight lines
Parallel lines
Area of a trapizoid
A=1/2(b1+b2)h
3 sided figure
Triangle
Less than 90 degrees
Acute angle
Two lines going into each other
Intersecting lines
Area of a parallelogram
A=bh
4 sided figure with 2 long sides and 2 short sides
Rectangle
More than 90 degreees
Obtuse angle
A shape that has 1 set of parallel lines
Trapizoid
Area of a composite figure
The sum of an area of the regular figures
No straight sided shape
Circle
Straight angle
180 degrees
A shape that has 2 sets of parallel lines
Square.