#20
An angle can be both acute and obtuse.
never true
By definition, acute angles are less than 90 degrees and obtuse angles are greater than 90 degree.
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#21
if a ray bisects a right angle, then each newly formed angle measured 45 degrees.
always true
"bisect" means to split up in half. Since right angle is 90 degrees, splitting it in half means 90/2 = 45.
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#22
If a ray bisects an angle, each newly formed angle measures 90 degrees.
sometimes true
if the angle bisected is a straight angle (180 degrees), then both the angles are 90 each. Othertimes, it is not true.
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#23
Two right angles are congruent.
always true
Two angles are congruent if their angle measures are the same. Since, it is given two of the angles are right angles, thus they are congruent.
