Answer:
An acute angle ("acute" meaning "small") is an angle smaller than a right angle. The range of an acute angle is between 0 and 90 degrees.
An obtuse triangle (or obtuse-angled triangle) is a triangle with one obtuse angle (greater than 90°) and two acute angles. Since a triangle's angles must sum to 180° in Euclidean geometry, no Euclidean triangle can have more than one obtuse angle.
Protractor: an instrument for measuring angles, typically in the form of a flat semicircle marked with degrees along the curved edge.
Degrees: a unit of measurement of angles, one three-hundred-and-sixtieth of the circumference of a circle.
Right Angel: an angle of 90°, as in a corner of a square or at the intersection of two perpendicular straight lines.
Straight Angle: an angle of 180°.
Step-by-step explanation: