Question

if a + b + c = 2 8 and ( AB + BC + CA )= 19 find ​

Answer 1

Answer:

Step-by-step explanation:

Given,

a+b+c=28

(AB+BC+CA)=19

we know that

(A+B+C)²=A²+B²+C²+2(AB+BC+CA)

28²=A²+B²+C²+2(19)

A²+B²+C²=784-38

               =748

hope you understand

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