Terminology_3

Question 1

A semicircle

Answer 1

1. is the figure contained by the diameter and the circumference cut off by it.
2. And the center of the semicircle is the same as that of the circle.

Question 2

Rectilineal figures are

Answer 2

1. those which are contained by straight lines (trilateral contained by three; quadrilateral contained by four; multilateral contained by more than four)

Question 3

Of trilateral figures, an equilateral triangle

Answer 3

is that which has its three sides equal,

Question 4

Of trilateral figures, an isosceles triangle

Answer 4

that which as two of its sides alone equal

Question 5

Of trilateral figures, an scalene triangle

Answer 5

that which as its three sides unequal

Question 6

Further, of trilateral figures, a right angled triangle

Answer 6

is that which has a right angle

Question 7

Further, of trilateral figures, an obtuse-angled triangle

Answer 7

that which has an obtuse angle

Question 8

Further, of trilateral figures, an acute-angled triangle

Answer 8

that which has its three angles acute

Question 9

of quadrilateral figures, a square

Answer 9

is that which is both equilateral and right-angled

Question 10

of quadrilateral figures, an oblong

Answer 10

that which is right angled but not equilateral

Question 11

of quadrilateral figures, a rhombus

Answer 11

that which is equilateral but not right angled

Question 12

of quadrilateral figures, a rhomboid

Answer 12

that which has its opposite sides and angles equal to one another but is neither equilateral nor right angled

Question 13

of quadrilateral figures, that are not contained in the previous definitions?

Answer 13

call trapezia

Question 14

Parallel straight lines

Answer 14

are straight lines which, being in the same plane and being produced indefinitely in both directions, do not meet one another in either direction