Question
In a classroom, 4 friends are seated at the points A, B, C and D as shown in Fig. 7.8. Champa and Chameli walk into the class and after observing for a few minutes Champa asks Chameli, “Don’t you think ABCD is a square?” Chameli disagrees. Using distance formula, find which of them is correct.
Fig. 7.8
Solution
Let A(3, 4), B(6, 7), C(9, 4) and D(6, 1) be the given points. Then
]
]We see that,
AB = BC = CD = DA
and AC = BD
Therefore, ABCD is a square.
Hence, Champa is correct.
