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 measure of two right angle 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 ……….. .