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neurologyYou need to know

• An acute angle is greater than `0^\circ` and less than `90^\circ`.
• A right angle is exactly `90^\circ`.
• An obtuse angle is greater than `90^\circ` and less than `180^\circ`.
• A reflex angle is greater than `180^\circ` and less than `360^\circ`.
• Angles at a point on a straight line add to `180^\circ`.
• Angles around a point add to `360^\circ`.
• Vertically opposite angles are equal because they are formed by two intersecting straight lines.
• The interior angles in a triangle add to `180^\circ`.
• An isosceles triangle has two equal sides and the two base angles opposite those equal sides are equal.
• The sum of the interior angles in an `n`-sided polygon is `(n-2) \times 180^\circ`.
• The sum of the exterior angles of any polygon, taking one exterior angle at each vertex, is `360^\circ`.
• A regular polygon has all sides equal and all interior angles equal.
• Each interior angle of a regular `n`-sided polygon is `\frac{(n-2) \times 180^\circ}{n}`.
• Each exterior angle of a regular `n`-sided polygon is `\frac{360^\circ}{n}`.
• Corresponding angles in parallel lines are equal and form matching positions on the two parallel lines.
• Alternate angles in parallel lines are equal and form a Z-shape between the two parallel lines.
• Co-interior angles in parallel lines add to `180^\circ` and form a C-shape between the two parallel lines.
• Bearings are measured clockwise from north and are written as three figures, such as `047^\circ` or `125^\circ`.

• Measure an angle accurately using a protractor by placing the centre on the vertex, lining up the baseline with one arm, and reading the correct scale.
• Draw an angle of a given size using a ruler and protractor, marking the required degree measure from a baseline and joining the mark to the vertex.
• Estimate the size of an angle by comparing it with key angles such as `90^\circ`, `180^\circ`, `270^\circ`, and `360^\circ`.
• Calculate missing angles in right angles, straight lines, around a point, triangles, and polygons by choosing the correct angle sum and subtracting known angles.
• Find missing angles using vertically opposite angles by identifying the intersecting straight lines and stating that the opposite angles are equal.
• Calculate unknown interior or exterior angles in regular polygons using the number of sides and the correct formula.
• Identify and calculate corresponding, alternate, and co-interior angles in parallel lines, giving the correct angle reason for each step.
• Solve multi-step angle problems by combining angle facts, including triangle sums, isosceles triangle base angles, angles on a straight line, angles around a point, and parallel line angle facts.
• Measure and draw bearings accurately by starting from north, measuring clockwise, and recording the bearing as a three-figure angle.