Question

IF angle A+B+C=9 and ab+bc+ca=23 then a^2+b^2+c^2

Answer 1

Step-by-step explanation:

(A+B+C)^2= A^2+ B^2 +C^2+ 2AB+ 2BC + 2CA

9^2 = A^2 +B^2+ C^2 +2×23

A^2+B^2+C^2= 81-46=35