T

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the name of the triangle

A, B, C

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three points

l1, l2, l3

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three lines

side1, side2, side3

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three sides of the triangle

side1, 'angle'=theta, side3

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side1 and side3 are the two sides of the triangle, and theta is the angle between them

n

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(optional) list of two names representing the names of the horizontal-axis and vertical-axis respectively

form(T)

returns the form of the geometric object (i.e., triangle2d if T is a triangle).

HorizontalName(T)

returns the name of the horizontal-axis; or FAIL if the axis is not assigned a name.

VerticalName(T)

returns the name of the vertical-axis; or FAIL if the axis is not assigned a name.

method(T)

the method to define the triangle T. They are ``points'' if T is defined from three points or three lines. ``sides'' if T is defined from three sides. ``angle'' if T is defined from two sides, and the angle between them.

DefinedAs(T)

returns the list of three vertices of T if T is defined from three points or three lines. the list of three sides of T if T is defined from three sides. the list of two sides and an angle in between if T is defined that way.

detail(T)

returns a detailed description of the triangle T.