Question

1. a polygon that has at least one diagonal outside the figure is: mark only one oval. regular convex concave equilateral 11. an angle that measures less than 90° is: mark only one oval. right acute obtuse straight 12. an angle that measures exactly 180° is: mark only one oval. acute right obtuse straight

Explanation:

1. A concave polygon has at least one diagonal outside the figure. Regular polygons have all sides and angles equal, convex polygons have all diagonals inside, and equilateral polygons have all sides equal.
2. An acute angle measures less than 90°. A right - angle measures 90°, an obtuse angle measures more than 90° but less than 180°, and a straight angle measures 180°.
3. A straight angle measures exactly 180°. An acute angle is less than 90°, a right - angle is 90°, and an obtuse angle is between 90° and 180°.

Answer:

1. Concave
2. acute
3. straight