# What is the area of the largest square that can be fit in a circle of radius 6 cm?

justaguide | College Teacher | (Level 2) Distinguished Educator

Posted on

To find the area of the largest square that can be fit in a circle, let’s see what happens when the square is drawn. We find that for a square all four corners of which lie on the circle, the diagonal of the square is equal to the diameter of the circle.

Here the radius is 6 cm and the diameter 12 cm. Now if a square has sides s, the diagonal has a length sqrt (s^2 + s^2) = s*sqrt 2

So s* sqrt 2 = 12

s = 12 / sqrt 2

The area of the square with side 12/ sqrt 2 is = 144 / 2 = 72.

Therefore the area of the largest square that can fit in a circle of radius 6 is 72.

neela | High School Teacher | (Level 3) Valedictorian

Posted on

We know that the equal chords are at equal distance from the centre. So if x is the chord length, then the perpendicular through the centre to the otherside is x. The maximum area of the square in the circle is a square with all 4 vertices on the circumferences.Therefore semi chord lengh and distance from the centre are equal in case of a square.

Therefore x^2+x^2 = r^2 .

So 2x^2 = r^2.

Or x = sqrt(r^2/2 ) = r/sqrt2, which is the unique side of the suare that could be inscribed in a circle having all its 4 vertices on the circumference. The area of the square is r^2/2 = 12^2/2 = 72 sq units, as the given radius is 12.