One straight angle is equivalent to the sum of two right angles.
Fill in the blanks with acute, obtuse, right or straight:
(a) An angle whose measure is less than that of a right angle is _______.
(b) An angle whose measure is greater than that of a right angle is _______.
(c) An angle whose measure is the sum of the measures of two right angles is _______.
(d) When the sum of the measures of two angles is that of a right angle, then each one of them is _______.
(e) When the sum of the measures of two angles is that of a straight angle, and if one of them is acute then the other should be _______.