Answer:
52
Step-by-step explanation:
Expand the trinomial - if this is confusing you can set
[tex]d=b+c[/tex]
And expand [tex](a+d)^2[/tex], then substitute the terms back in afterwards.
[tex](a+b+c)^{2}=100\\ (a+b+c)^2=a^2+b^2+c^2+2ab+2bc+2ca\\100=a^2+b^2+c^2 +2(ab+bc+ca)\\100-2(24)=a^2+b^2+c^2\\100-48=52[/tex]
