أكاديميا - كولنز - معاجم الجيب العلمية - الرياضيات - انكليزي -فرنسي -عربي الحرف ٥_ r

Academia - Collins - Pocket Scientific Dictionaries - Mathematics - English - French - Arabic Letter 5_ R

right anlge
angle m droit

Right angle. An angle measuring 90°, or 2/π
radian angle. It is a quarter of a full turn.

A common way to symbolize a right angle.

Roman numerals
chiffres mpl romains

Roman numerals. A system for writing natural numbers used by the Romans:

I =1
V=5
X=10
L=50
C=100
D=500
M=1000

All other numbers are formed using combinations of the letters above:

( 1 before 5 )
( 1 after 5 )
( 7 after 20 )
( 10 before 100 )

root
racine f

Root . The root of an equation is the value that is substituted in the equation for the unknown to make the equation true.

For example:

The roots of the equation x2-7x+12=0 are 3 or 4.

32-7x3+12=0 because

42-7x4+12=0 and

22-7x2+12≠0 and not 2 is a root because

A number is said to be a root of another number if the other can be formed by taking the powers (base) of the first number. For example:

5 is the square root of 25 because 5×5 or 52=25
2 is the cube root of 8 because 2×2×2 or 8=23
3 is the quintic root of 243 because 243=36

rotation
rotation f

Rotation. Rotation is a geometric transformation in which each point rotates through the same angle. In a plane, rotation is done around a single point called the center of rotation. The center of rotation is the only point that does not change its position after rotation.

A triangle rotated 90° around point 0.

A rectangle rotated 90° around point 0.

To distinguish between clockwise and counterclockwise rotation, the signs + and - are used, where - is for clockwise rotation and + is for counterclockwise rotation. + 60° means 60° counterclockwise, while - 90° means 90° clockwise.

Note that + 90° means - 100 270° and that - 100 =
+ 260 . . . etc.
The rotation of its center (0.0) can be expressed in matrix form, for example:

A body can rotate in space around an axis of rotation. For example: A cone is formed when an isosceles triangle is rotated around its axis of symmetry. See the following figure.

Rotating a triangle gives a cone

rounding off
arrondissement m

Rotation. Rounding is a method of approximating a number from a number whose digits are less than zero.

For example:

Rounding £16.25 to the nearest £16 = £1.

Rounding 275 meters to the nearest 100 meters = 300 meters.

Rounding 25471 to the nearest 25000 = 1000

When the first digit to be ignored is 0, 1, 2, 3, or 4, we round down, and when it is 5, 6, 7, 8, or 9, we round up. For example: Rounding 27381 to the nearest 100 is 27400 (rounding up).

Rounding 42.73 to the nearest 1 is 43 (rounding up) Rounding 6.1238 to the nearest 1/10 is 6.1 (rounding down)

Rounding 865 to the nearest 10 is 870 (rounding up)

row
line f

A row. A list of numbers or letters written horizontally.
For example:
1 2 3 4 5 6

(2.5) Coordinates are written as a row.
This matrix has two rows.
(17642) A matrix that contains only one row
It is called a row matrix.

ruler
line f

Ruler. A straight edge marked in linear units
It is used to measure distances.