Question 914529
Re TY '+' didn't come thru :), Principle the same...
A+B = 10  0r A = 10-B 
B+C = 12  0r C = 12-B
A+C = 15
(10-B) + (12-B) = 15
22-2B = 15 
 7 = 2B,  B = 3.5 , A = 6.5 {{{10-3.5}}}, C = 8.5 {{{12-3.5}}}
.............
AB = 10  0r A = 10/B 
BC = 12  0r C = 12/B
AC = 15
{{{(10/B)(12/B)}}} = 15
{{{(10*12/15)}}} = B^2 
B^2 = 8
B = ± {{{sqrt(8)}}} = ± {{{sqrt(4*2)}}}
B = ± 2√2
 A = 10/B  = ± {{{10/(2sqrt(2))}}} = ±{{{5sqrt(2)/2}}}