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1 Primary & Middle School Mathematics1–9 年级在线 2 High School Mathematics10–12 年级在线 3 University Mathematics — Year 1本科一年级在线 4 University Mathematics — Year 2本科二年级在线 5 University Mathematics — Year 3本科三年级在线

1 Primary & Middle School Physics1–9 年级在线 2 High School Physics10–12 年级在线 3 University Physics — Year 1本科一年级在线 4 University Physics — Year 2本科二年级在线 5 University Physics — Year 3本科三年级在线

1 School Chemistry — Grades 1 to 121–12 年级在线 2 University Chemistry — Year 1本科一年级在线 3 University Chemistry — Year 2本科二年级在线 4 University Chemistry — Year 3本科三年级在线

1 Primary & Middle School Biology1–9 年级在线 2 High School Biology10–12 年级在线 3 University Biology — Year 1本科一年级在线 4 University Biology — Year 2本科二年级在线 5 University Biology — Year 3本科三年级在线

1 Primary & Middle School Earth and Space Sciences1–9 年级在线 2 High School Earth and Space Sciences10–12 年级在线 3 University Earth and Space Sciences — Year 1本科一年级在线 4 University Earth and Space Sciences — Year 2本科二年级在线 5 University Earth and Space Sciences — Year 3本科三年级在线

1 Markets I: The Ecosystem and Exchange-Traded Markets市场在线 2 Markets II: Rates, FX and Credit市场在线 3 Markets III: Commodities, Energy and Crypto市场在线 4 Quantitative Methods方法在线 5 Derivatives and Volatility衍生品在线 6 Rates, Credit, XVA and Risk利率、信用与风险在线 7 Research Craft: Predictors, Backtests, Measurement, Portfolios研究在线 8 Strategies I: Equities and Futures策略在线 9 Strategies II: Volatility, Relative Value, Macro and the Bank Desks策略在线 10 Microstructure and Execution交易执行在线 11 Market Making and High-Frequency Trading做市在线 12 Machine Learning for Markets机器学习在线 13 Low-Latency Software技术在线 14 Networks, Hardware and Trading Infrastructure技术在线 15 Research, Data and Risk Platforms技术在线 16 The Desk and the Firm公司运营在线 17 The Industry: Firms, Roles and Careers职业发展在线 18 Interviews I: Maths, Probability and Speed职业发展在线 19 Interviews II: Markets, Trading Games and the Final Round职业发展在线 20 Interviews III: Code职业发展在线

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Mathematics · 术语表

什么是 Angle？

Definition 40.7 Primary & Middle School Mathematics · 第 40 章 — Lines, Circles and Angles

Two rays $[AB)$ and $[AC)$ with the same starting point $A$ form the angle $\widehat{BAC}$ ; the point $A$ is its vertex (always the middle letter!). Angles are measured in degrees ( $^\circ$ ), from $0^\circ$ to $360^\circ$ for a full turn. An angle is:

right if it measures $90^\circ$ ;
acute if it measures less than $90^\circ$ ;
obtuse if it measures between $90^\circ$ and $180^\circ$ ;
straight if it measures $180^\circ$ (the two rays form a line).

The four families of angles. The right angle (90) is the reference: acute means smaller, obtuse means larger. — The four families of angles. The right angle ( $90^\circ$ ) is the reference: acute means smaller, obtuse means larger.

示例

Example 40.9

Before measuring, estimate! An angle slightly more open than the corner of a sheet of paper is a little over $90^\circ$ ; half a right angle is $45^\circ$ ; a third of a right angle is $30^\circ$ . If your protractor says $150^\circ$ for an angle that looks acute, you read the wrong scale: the correct measure is $180^\circ - 150^\circ = 30^\circ$ .

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