A) 67
B) 77
C) 57
D) 37
Correct Answer: B
Solution :
(b): Focus on what is to be found \[{{a}^{2}}+{{b}^{2}}+{{c}^{2}}={{\left( a+b+c \right)}^{2}}-2\left( ab+bc+ca \right)\]\[={{\left( 15 \right)}^{2}}-2\times 74\] \[=225-148=77.\]You need to login to perform this action.
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