**Question:**

All the angles of a quadrilateral are equal. What special name is given to this quadrilateral?

**Solution:**

We know that, sum of all angles in a quadrilateral is 360°.

If ABCD is a quadrilateral,

∠A+ ∠B+ ∠C + ∠D = 360° …(i)

But it is given all angles are equal.

∠A = ∠B = ∠C = ∠D From Eq. (i)

∠A + ∠A + ∠A + ∠A = 360°

=> 4 ∠A = 360°

∠A = 90°

So, all angles of a quadrilateral are 90°.

Hence, given quadrilateral is a rectangle.