Angles
Angles represent the space between two lines (measured in degrees). Let's take a look at different types of angles.
| Type | Description |
|---|---|
| Acute Angle | it is less than 90° |
| Right Angle | it is exactly 90° |
| Obtuse Angle | it is greater than 90° but less than 180° |
| Straight Angle | it is exactly 180° |
| Reflex Angle | it is greater than 180° but less than 360° |
| Full Rotation | it is 360° exactly |
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Opposite Angles
Opposite angles are across the transversal. Opposite angles are equal.
Corresponding Angles
Corresponding angles are in the same position relative to lines intersected by a transversal. Corresponding angles are equal when the two lines intersected by the transversal are parallel.
Alternate Angles
Alternate angles are in opposite positions relative to a transversal intersecting two lines. Alternate angles are equal when the two lines intersected by the transversal are parallel.
Co-interior Angles
Co-interior angles are on the same side of an transversal line when it intersect two other lines. Co-interior angles add to \(180^\circ\).
Supplementary Angles
Two angles are supplementary when they add up to 180 degrees (they make a straight line).
\(\angle A\) and \(\angle B\) below form a straight line so they must add to 180 degrees.
Complementary Angles
Two angles are complementary when they add up to 90 degrees (a right angle).
\(\angle{DAC}\) and \(\angle{CAB}\) form a right angle and would add up to 90 degrees.
Refer to the figure below. Guess which angles correspond with each type then press the button to show the answer.
