# data[].attributes.headline
Line segment- a part of a line that consists of one endpoint and all the points of the line on one side of the endpoint. 

# data[].attributes.subject
Line segment- a part of a line that consists of one endpoint and all the points of the line on one side of the endpoint. 

# data[].attributes.headline
Right angle- an angle whose measure is exactly 90 degrees.

# data[].attributes.subject
Right angle- an angle whose measure is exactly 90 degrees.

# data[].attributes.headline
Postulate 1-2- if two direct lines intersect, then they intersect in exactly one point.

# data[].attributes.subject
Postulate 1-2- if two direct lines intersect, then they intersect in exactly one point.

# data[].attributes.headline
Postulate 1-3- if two distant planes intersect, then they intersect in exactly one line.

# data[].attributes.subject
Postulate 1-3- if two distant planes intersect, then they intersect in exactly one line.

# data[].attributes.headline
Coplanar- points that lie in the same plane.

# data[].attributes.subject
Coplanar- points that lie in the same plane.

# data[].attributes.headline
Line- represented by a straight path that extends in two opposite direction without end and has no thickness. 

# data[].attributes.subject
Line- represented by a straight path that extends in two opposite direction without end and has no thickness. 

# data[].attributes.headline
Congruent angle- angle with the same measure.

# data[].attributes.subject
Congruent angle- angle with the same measure.

# data[].attributes.headline
Congruent segments- segments that have the same length.

# data[].attributes.subject
Congruent segments- segments that have the same length.

# data[].attributes.headline
Straight angle- an angle whose measures exactly 180 degrees.

# data[].attributes.subject
Straight angle- an angle whose measures exactly 180 degrees.

# data[].attributes.headline
Obtuse angle- an angle whose measure is bigger than 90 degrees, but less that 180 degrees.

# data[].attributes.subject
Obtuse angle- an angle whose measure is bigger than 90 degrees, but less that 180 degrees.

# data[].attributes.headline
Vertical angle- a pair of non-adjacent angles whose sides are opposite rays.

# data[].attributes.subject
Vertical angle- a pair of non-adjacent angles whose sides are opposite rays.

# data[].attributes.headline
Acute angle- an angle whose measure is between 0 and 90, but not including 90.

# data[].attributes.subject
Acute angle- an angle whose measure is between 0 and 90, but not including 90.

# data[].attributes.headline
Parallel lines- lines that do not intersect and are coplanar. 

# data[].attributes.subject
Parallel lines- lines that do not intersect and are coplanar. 

# data[].attributes.headline
Rectangle- polygon with four straight sides and four right angles, with unequal adjacent sides. 

# data[].attributes.subject
Rectangle- polygon with four straight sides and four right angles, with unequal adjacent sides. 

# data[].attributes.headline
Square- a polygon with four equal sides and four right squares.

# data[].attributes.subject
Square- a polygon with four equal sides and four right squares.

# data[].attributes.headline
Circle- a round plane figure whose boundary consists of points equidistant from a fixed point (the center).

# data[].attributes.subject
Circle- a round plane figure whose boundary consists of points equidistant from a fixed point (the center).

# data[].attributes.headline
Point- indicates a location and has no size. 

# data[].attributes.subject
Point- indicates a location and has no size. 