Geometry: Types of Angles and Properties

Types of Angles

• Acute Angle: An angle whose measure is between 0° and 90°.
• Right Angle: An angle whose measure is exactly 90°.
• Obtuse Angle: An angle whose measure is between 90° and 180°.
• Straight Angle: An angle whose measure is exactly 180°.
• Reflex Angle: An angle whose measure is between 180° and 360°.

Angle Properties

• Complementary Angles: Two angles whose sum is 90°.
• Supplementary Angles: Two angles whose sum is 180°.
• Adjacent Angles: Two angles that share a common vertex and side.
• Vertical Angles: Two angles formed by two intersecting lines.

Measuring Angles

• Degree: A unit of measurement for angles, where 1 degree is 1/360 of a full circle.
• Minutes and Seconds: Subunits of degrees, where 1 minute is 1/60 of a degree and 1 second is 1/60 of a minute.

Angle Relationships

• Congruent Angles: Two angles that have the same measure.
• Equivalent Angles: Two angles that have the same measure or can be made to have the same measure by adding or subtracting multiples of 360°.
• Alternate Interior Angles: Two angles formed by two lines and a transversal, where one angle is inside the region between the two lines and the other angle is outside the region.

Types of Angles

• Acute angles measure between 0° and 90°.
• Right angles are exactly 90°.
• Obtuse angles measure between 90° and 180°.
• Straight angles are exactly 180°.
• Reflex angles measure between 180° and 360°.

Angle Properties

• Complementary angles add up to 90°.
• Supplementary angles add up to 180°.
• Adjacent angles share a common vertex and side.
• Vertical angles are formed by two intersecting lines.

Measuring Angles

• A degree is a unit of measurement for angles, equal to 1/360 of a full circle.
• Minutes are subunits of degrees, with 1 minute equal to 1/60 of a degree.
• Seconds are subunits of minutes, with 1 second equal to 1/60 of a minute.

Angle Relationships

• Congruent angles have the same measure.
• Equivalent angles have the same measure or can be made equivalent by adding or subtracting multiples of 360°.
• Alternate interior angles are formed by two lines and a transversal, with one angle inside and one angle outside the region between the lines.

Explore the different types of angles, including acute, right, obtuse, straight, and reflex angles, and learn about complementary, supplementary, and adjacent angles.