Bearings and Scale Drawings | 方位角与比例绘图

📚 Bearings and Scale Drawings | 方位角与比例绘图

Bearings and scale drawings are core skills in the Cambridge KS3 mathematics curriculum. They connect geometry, proportional reasoning, and real-world navigation. This revision note explains the rules and methods you need for questions such as Exercise 2 on page 195.

方位角与比例绘图是剑桥 KS3 数学课程中的核心技能，它们把几何、比例推理和现实导航联系起来。本复习笔记将讲解第 195 页练习 2 类题目所需的规则与方法。

1. What Are Bearings? | 什么是方位角

In navigation and map work, a bearing is a direction measured as an angle from north. It tells you the direction of one point from another.

在导航和地图作业中，方位角是从正北方向测量的角度，用来表示一个点相对于另一个点的方向。

Bearings are always measured clockwise from the north line. The angle is written using three digits, such as 045° or 210°.

方位角始终从正北线沿顺时针方向测量，并使用三位数字表示，例如 045° 或 210°。

A bearing answers the question: ‘From A, in which direction should I travel to reach B?’ It does not give a distance, only a direction.

方位角回答的问题是：“从 A 点出发，我应向哪个方向行进才能到达 B 点？”它只给出方向，不给出距离。

2. Three-Figure Bearings Rules | 三位数方位角规则

There are three essential rules for writing bearings correctly:

正确书写方位角有三条基本规则：

• Always measure from north. / 始终从正北开始测量。

• Always rotate clockwise. / 始终沿顺时针方向旋转。

• Always give the answer as three digits. / 始终用三位数字表示答案。

For example, due east is 090°, due south is 180°, due west is 270°, and due north is 000° or 360°.

例如，正东为 090°，正南为 180°，正西为 270°，正北为 000° 或 360°。