Mat_5th_UD3_Angles
- 1. UNIT 3 ANGLES by Maria Adrover CEIP CALONGE
- 2. DEFINITION and PARTS of an angle The amount of turn between two straight lines that have a common end point (the vertex).
- 3. USING A PROTRACTOR Set the protractor so that: The vertex of the angle match the protractor centre. One angle arm should match the base line. Read the score, this is the angle measure. If the arms of the angles are too short... Make them longer using a ruler and a pencil
- 4. The protractor help us to measure angles. The angles are measured using degrees (º)
- 5. CONSTRUCTING ANGLES Let's construct a 45º angle: 1. Trace a line starting from point A. 2. Match point A with the protractor centre. The traced line should coincide with the protractor base line. 3. Mark the 45º with a litle point using the pencil. 4. Join point A and the 45º mark with a line.
- 7. COMPLETE ANGLES ➲ A 360º angle is a complete angle
- 8. RELATION BETWEEN ANGLES CONSECUTIVE: They have the vertex and one arm in common. ADJACENT: They have the vertex and one arm in common and they form a straight angle. INVERSE: They have the vertex and the arms in common. They are two intersecting lines.
- 9. ANGLE BISECTOR The bisector is a straight line that splits an angle into two equal angles.
- 10. LOOKING FOR THE BISECTOR 1. Put de compass needle on the angle vertex (O) and mark a little arc on each angle arm (points A and B). 2. Mark an ark from point A. 3. With the same compass opening, mark another arc from point B. 4. Join, using a ruler, the angle vertex (O) with the crossing point of the arcs.
- 11. LINE BISECTOR ➲ The line bisector is the perpendicular line that divides a segment in two equal parts
- 12. LOOKING FOR THE LINE BISECTOR 1. Open the compass (bigger than the half of the segmet AB). Trace an arc from A. 2. With the same compass opening, trace an arc from point B. 3. Join, using a ruler, the two meeing points.