Max Maths, Year 5, Learn together, Angles on a straight line (3)

In the Year 5 maths lesson on angles, students learn a fundamental property of geometry: the sum of the angles on a straight line is always 180 degrees. This concept is introduced through a simple equation, a + b + c = 180°, which represents the sum of three angles, a, b, and c, that form a straight line. To reinforce this idea, students are presented with a practical example where they need to find the value of an unknown angle, labelled as 'm', on a straight line PQR. With one of the angles given as 60°, students are encouraged to perform a subtraction operation to find the value of 'm'. By subtracting 60° from 180°, they discover that 'm' equals 120°.

To further engage with the concept, students are then tasked with using a protractor to measure given angles on their own. They measure angles a, b, and c, and upon adding these measurements together, they should find that the total equals 180°, thus confirming the rule that the sum of angles on a straight line is 180°. This hands-on activity not only solidifies their understanding but also provides practice in using a protractor, an essential tool for measuring angles. For additional exercises and to continue their exploration of angles, students are directed to complete the activities on pages 49 to 52 of their workbook.