A geometry problem by Naman Sehgal

Geometry Level 2

A square is inscribed in a circle and a circle is inscribed in that square. What will be the ratio of the area of the bigger circle to that of the smaller circle?

4 2 3 5

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

7 solutions

Shivang Agarwal
Jul 8, 2014

Let the side of the square be x then its diagonal will be root 2 * x which will be the diameter of the circumcircle and similarly the the diameter of the incircle will be x and hence ratio will be

pie * (root 2 x) (root 2* x)/ pie (x) (x)

which will give u 2

Thanks! And it's actually said spelled as 'pi'. :)

Alexander Paul - 6 years, 11 months ago

I think most of the students suggest this!!!!

Ali Bahramishad - 6 years, 11 months ago

i miscomputed......

Yukimura Sanada - 6 years, 11 months ago

In smaller circle its diameter is a ( the side of squre).in bigger circle diameter is a*root2. from hypotanous of squre..so area is 2 times.

Ruman Hasan - 6 years, 10 months ago

He will the diametre of. Big circle is root 2*

Dheeraj pandey - 6 years, 11 months ago

Log in to reply

the diagonal of the square = diameter of outer circle....And diagonal of square = sq.root(2) * side

V Vishnu Prasad - 6 years, 11 months ago

ya this is a simple and straight forward explanation

mohammad asgar - 6 years, 11 months ago

Yeah it's right

vijay krishnan - 6 years, 11 months ago

phi r2/ phi r/root2 ka square=2

Abhay Gupta - 6 years, 11 months ago

Its tricky to me

Takumi Fujiwara Jimenez - 6 years, 11 months ago

Couldn't compute properly

Sudipto Chowdhury - 6 years, 11 months ago
Esrael Santillan
Jul 16, 2014

Let S be the side of the square. Then the radius of small circle is r = S 2 r=\frac{S}{2} , and the radius of big circle is R = ( S 2 ) 2 + ( S 2 ) 2 = S 1 2 R=\sqrt{\left(\frac{S}{2}\right)^2+\left(\frac{S}{2}\right)^2} = S\sqrt{\frac{1}{2}} . Then the ratio of their area is: A r e a b i g A r e a s m a l l = π R 2 π r 2 = ( R r ) 2 = ( S 1 2 ( S 2 ) ) 2 = ( 2 1 2 ) 2 = 4 ( 1 2 ) = 2 \frac{Area_{big}}{Area_{small}}=\frac{\pi R^2}{\pi r^2} = \left(\frac{R}{r}\right)^2 = \left(\frac{S\sqrt{\frac{1}{2}}}{\left(\frac{S}{2}\right)}\right)^2 = \left(2\sqrt{\frac{1}{2}}\right)^2=4\left(\frac{1}{2}\right)=2

Mahesh Kumar
Jul 14, 2014

The bigger circle is directer circle to the smatller one that's it has radical2 times radius so area is double

Let 1 1 be the diameter of the bigger circle, that is also the diagonal of the square which is a hypotenuse of a right triangle. By pythagorean theorem, the side length of the square is 1 2 \dfrac{1}{\sqrt{2}} which is also the diameter of the smaller circle. By similar polygons, the ratio of the area of the bigger circle to the area of the smaller circle is

1 2 ( 1 2 ) 2 = 1 1 2 = \dfrac{1^2}{\left(\dfrac{1}{\sqrt{2}}\right)^2}=\dfrac{1}{\dfrac{1}{2}}= 2 \color{#D61F06}\large \boxed{2}

F F
Jul 25, 2016

this is very easy any math reader can solve it ..

Christian Daang
Sep 18, 2014

The Diameter of the: big Circle is s_/2

Small Circle is s

where in, s is the side of the Square

The ratio of the area will be:

[(s_/2)/2]^2 pi : (s^2) pi

2:1

Giving us, 2...

Gerardo Lozada
Jul 14, 2014

Larger circle area = pi r^2. Radius of smaller circle is r/sqrt(2) hence its area is (pi r^2)/2. Area of bigger circle/area of smaller circle =2.

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...