Today's topic that we are focusing on is **Bearings. **Bearings are used in navigation to identify (as a measure of turn) where the direction of one object is in relation to another. You need to remember that bearings are calculated from **North**, in a **clockwise** direction and given as a **three digit** value. Be careful with sentence structure as bearings are measured FROM the object (normally the second point in the question). When calculating more complex bearings knowledge of angles in parallel lines is useful (particularly co-interior angles). The harder questions will involve speed, time, perpendicular lines and maybe the use of Pythagoras' theorem and trigonometry.

On day 80 of our countdown to exams, we take a look at the topic of Circle theorems. There are 7 key circle theorems you need to be able to recall when faced with questions involving missing angles in circles. In order to secure full marks, you will need to justify your reasoning by stating one or more of the circle theorems (not just the shape) along with other angle facts you know (straight line, triangle, around point etc.).

Today, we are looking at the **Trigonometry Ratios. **Trigonometry is usually used to calculate missing side lengths and angles in right-angled triangles. There are three functions you need to aware of; the Sine, Cosine and Tangent Functions and these are related to the lengths of the key terms of the right-angled triangle (Opposite, Adjacent and Hypotenuse). They are simply one side of a right-angled triangle divided by another and will have a specific value dependent upon the angle marked theta (or x).

You are required to know the specific values for each function when given an angle. It will be important to remember the three tables provided in this snapshot.

For day 42, we are focusing on **angles in parallel lines.** It is fairly straight forward to calculate the angles on a straight line as we can use the vertically opposite angles reasoning or angles in a straight line reasoning.

When you want to compare one angle on one parallel line to another angle on a different parallel line there are three types of angle reasoning you will need to state. (Alternate, Corresponding, Co-Interior)

On day 41, we start by taking a look at calculating the missing **angle in triangles** (add up to 180 degrees). It is important to aware of the Isosceles and Equilateral triangles as they have very specific angle properties. We then move onto **angles in polygons** which can be found by using a special formula. If in doubt, use the fact that the number of triangles in a shape is always two less than the number of sides.

If in doubt, use the fact that the number of triangles in a shape is always two less than the number of sides.

You will have to be able to calculate the exterior angle of a shape as well (all exterior angles make 360 degrees, Interior + Exterior = 180 degrees)

On day 40, we turn our attention to Angle facts. An angle is a measure of turn and is measured in degrees. You should be able to classify the different types of angles based on their size and use that information to be able to calculate missing angles in straight lines and around a point. Calculating missing angles is achieved by subtracting angles you already know.