the complementary  angle  of  an   given  angle  is  2/5  th  of  the  supplementary  angle.  what  is   the  measure  of  given  angle?
Ans:
Let the angle be x.
Sum of an angle and complementary angle is 90.
Sum of an angle and supplementary angle is 180.
Complementary angle = 90 - x
Supplementary angle = 180 - x
Given that 
i.e.


 or 

Check: If x is 30, complementary angle = 60, supplementary angle = 150
60 is 2/5 times 150. Correct!

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