Final answer:
An acute angle has a measure less than 90 degrees, a right angle has a measure of exactly 90 degrees, and an obtuse angle has a measure greater than 90 degrees but less than 180 degrees. Angles are formed by two rays with a common endpoint called the vertex. Congruent angles have the same measure, complementary angles have a sum of 90 degrees, and supplementary angles have a sum of 180 degrees. Adjacent angles share a side and a vertex, while vertical angles are nonadjacent angles formed by intersecting lines.
Step-by-step explanation:
1. An angle whose measure is less than 90 degrees is an acute angle.
2. An angle whose measure is exactly 90 degrees is a right angle.
3. An angle whose measure is greater than 90 degrees but less than 180 degrees is an obtuse angle.
4. An angle is a figure formed by two rays with a common endpoint.
5. The common endpoint shared by the two sides of an angle is called the vertex.
6. Two angles that have the same measure are called congruent angles.
7. If the sum of the measures of two angles is 90 degrees, then the angles are complementary angles.
8. If the sum of the measures of two angles is 180 degrees, then the angles are supplementary angles.
9. Two angles that share a side and a vertex are adjacent angles.
10. Two nonadjacent angles formed by intersecting lines are vertical angles.