question_answer

A, B, C and D are four angles at a point so that A+B+C+D=4 right angles, out of these A and B are acute angles while C and D are obtuse angles. Which of the following relations may be true?

1. A+B=C+D

2. A+C=B+D

3. A+D=B+C

A)  2 and 3 only       

B)  1 and 3 only

C) 1 and 2 only     

D) 3 only

Correct Answer: A

Solution :

 The following relations may be true                 (i) \[\angle A+\angle C=\angle B+\angle D\] or                 (ii) \[\angle A+\angle D=\angle B+\angle C\]