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Question
In a pentagon ABCDE, show that `bar"AB" + bar"AE" + bar"BC" + bar"DC" + bar"ED" = 2bar"AC"`
Solution
LHS = `bar"AB" + bar"AE" + bar"BC" + bar"DC" + bar"ED"`
`= (bar"AB" + bar"BC") + (bar"AE" + bar"ED" + bar"DC")`
`= bar"AC" + bar"AC"`
`= 2bar"AC"` = RHS
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