**Distance Formula CBSE NCERT solutions Chapter 7 Exercise 7.1 Question 5**

**5**. In a classroom, 4 friends are seated at the points **A (3, 4), B (6, 7), C (9, 4) and D (6, 1)**. 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.

**Solution:**

We have **A = (3,4), B = (6, 7), C = (9, 4) and D = (6, 1)**

Using **Distance Formula** to find distances **AB, BC, CD and DA**, we get

Therefore, All the sides of **ABCD** are equal here. ** (1)**

Now, we will check the length of its diagonals.

So, Diagonals of **ABCD** are also equal. **(2)**

From **(1)** and **(2)**, we can definitely say that **ABCD** is a **square**.

Therefore, **Champa is correct**.