i. If a point C be taken in a line AB, the parts AC, CB are called segments, and C a point of division.
ii. If C be taken in the line AB produced, AC, CB are still called the segments of the line AB; but C is called a point of external division.
iii. A parallelogram whose angles are right angles is called a rectangle.
iv. A rectangle is said to be contained by any two adjacent sides. Thus the rectangle ABCD is said to be contained by AB, AD, or by AB, BC, &c.
v. The rectangle contained by two separate lines such as AB and CD is the parallelogram formed by erecting a perpendicular to AB, at A, equal to CD, and drawing parallels: the area of the rectangle will be AB.CD.
