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a straight line from one side of a round object, particularly a circle, passing through the center and joining the other side
直径
the length of a straight line drawn from the center of a circle to any point on its outer boundary
半径
the relation between two amounts indicating how much larger one value is than the other
比率, 比例
(mathematics) a number less than one, called a fraction, that is represented as a period followed by the number of tenths, hundredths, etc.
小数, 十进制数
(mathematics) a quantity whose value changes according to another quantity's varying value
函数
very great in number, amount, or size and seeming to be without end or limit
无尽的, 无限的
a number that indicates the position of something in a sequence, such as third, second, etc.
序数, 序列号
each of the two symbols [ ] used to indicate that the enclosed numbers or words should be considered separately
方括号, 括号
(geometry) a shape that is not two-dimensional because it has height, width, and length
固体, 立体
a standard of measurement that is based on the kilogram, the meter, and the liter
公制系统
a unit for measuring oil and beer that equals 42 US gallons or 35 imperial gallons for oil and 36 imperial gallons for beer
桶, 酒桶
a measure of length that equals the distance traveled between two steps during a walk
步幅, 步速
a measure equal to 16 fluid ounces, often used for measuring liquids such as beer or milk
品脱, 升
a unit of volume measurement the United States for liquids, equal to 32 fluid ounces or approximately 946 milliliters
夸脱（体积单位）, 夸脱（美国液体单位）
the distance traveled in miles in relation to the time passed when doing so
每小时英里数, 每小时行驶的英里数
(mathematics) a quantity that is capable of assuming different values in a calculation
变量, 未知数
