Availability, in the context of a computer system, refers to the ability of a user to access information or resources in a specified location and in the correct format.
Defined, the triangle proportionality theorem states that if you draw a line parallel to one of the sides of a triangle that also crosses the other two sides, then that line will divide the two sides in a proportional way.
An isosceles triangle has two sides of equal length. An isosceles triangle also has two angles of the same measure, namely the angles opposite to the two sides of the same length; this fact is the content of the isosceles triangle theorem, which was known by Euclid.