How to do this calculation?

I'm assuming that you have

 (5+2.5sqrt(3))/(25/4*sqrt(3) )   =

5 / (25/4*sqrt(3) )    +  2.5sqrt (3) / (25/4 * sqrt (3) )  =

5 / (6.25 sqrt (3) )   +  2.5sqrt (3) / ( 6.25 * sqrt (3) )   =

5 / (6.25 sqrt (3) )   +  2.5 / ( 6.25  ) 

.8 / sqrt (3)   +  .4      =        rationalize the denominator in the frist fraction

.8sqrt (3) / [ sqrt (3) * sqrt (3) ]  +   .4  =

.8 sqrt (3) / 3  +   .4   =              get a common denominator

[.8sqrt (3)  + .4 (3)]  / 3  =

 [ .8 sqrt (3)  + 1.2 ]  / 3  =

.4 [ 2sqrt (3)  + 3 ]  / 3  =

(.4/3) [ 2sqrt (3)  + 3 ]  =

(4/30) [ 2sqrt (3) + 3 ] =

(2/15) [ 2sqrt (3) + 3  ]  ≈  .861880