You can 
put this solution on YOUR website! mÐ1:mÐ2 = 1:5. Find mÐ2
You have to know the measure of the sum of mÐ1 + mÐ2.
Otherwise you can't do the problem.
Were you told that Ð1 and Ð2 are 
complementary angles? Like this?:
|  /
|1/
|/2
 ¯¯¯¯¯¯
If so, then mÐ1 + mÐ2 = 90°
Let m<2 = x.  Then mÐ1 + x = 90°
                       mÐ1 = 90°-x
mÐ1:mÐ2 = 1:5
(90°-x):x = 1:5
Product of the means = product of the extremes
1x = 5(90° - x) 
 x = 450° - 5x 
6x = 450°
 x = 75°    
So mÐ2 = 75° 
Or, were you told that Ð1 and Ð2 are 
supplementary angles? Like this?:
       \    
        \  
        1\2 
 ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
If so, then mÐ1 + mÐ2 = 180°
Let mÐ2 = x.  Then mÐ1 + x = 180°
                       mÐ1 = 180°-x
mÐ1:mÐ2 = 1:5
(180°-x):x = 1:5
Product of the means = product of the extremes
1x = 5(180 - x) 
 x = 900° - 5x 
6x = 900°
 x = 150°    
So mÐ2 = 150° 
Edwin