Hope this helps you and good-luck
Because all 3 sides are given for both triangles you can use the SSS theorem
1/2+ 1/4
= 2/4+ 1/4
= 3/4
1/12+ 1/6
= 1/12+ 2/12
= 3/12
= 1/4
Therefore, 1/4+ 1/6+ 1/12
= (1/12+ 1/6)+ (1/12+ 1/6)
= 2*(1/12+ 1/6)
= 2* (1/4)
= 2/4
= 1/2
Hope this helps~