In this activity, you will need to find missing angles.
Missing angles on a straight line:
Angles on a straight line add up to 180°.
To calculate a missing angle on a straight line, take away the known angle from 180°.
180° - 55° = 125°
Missing angles in a full turn:
Angles in a full turn add up to 360°.
To calculate a missing angle in a full turn, take away the known angle from 360°.
360° - 105° = 255°
Missing angles on intersecting lines:
All 4 angles will add up to 360°.
Opposite angles on a cross are equal.
360° - 72° - 72° = 216°
216° ÷ 2 = 108°
Both missing angles are 108°
Missing angles in quadrilaterals:
A quadrilateral is any shape with 4 sides.
For example: square, rhombus, trapezium, parallelogram.
The angles in a quadrilateral add up to to 360°.
360° - 82° - 82° - 98° = 98°
We can also see that, in this trapezium, opposite angles are the same.