Each of the small circles in a figure has 1cm radio. The center circle is tangent to each of the six surrounding it, these being tangent to the big circle and its nearest neighbors. What is the area in cm^2 of the shaded area?

A)\( \pi\) B)1.5\(\pi\) C)\(\tau\) D)3\(\pi\) E)3.5\(\pi\)

The picture of the Circle

buubleman Nov 30, 2015

#3**0 **

I wonder if it is blocked for me. Because all i see is blank XD.

What did it look like? if you could describe it.

-Hay

Guest Nov 30, 2015

#4**0 **

It's proably blocked for you as i can clearly see it. i don't really know how to describe it!

buubleman Nov 30, 2015

#5**+10 **

Let us imagine that the big circle is completletly shaded and no smaller circles exist......the area of this circle = pi(3cm)^2 = 9pi cm^2

And the area of the 7 smaller congruent circles is 7*pi (1 cm)^2 = 7pi cm^2

And these are tangent to each other and to the larger circle

Then, the area of the shaded part left after the 7 smaller circles are inserted nto the larger circle =

pi ( [3cm]^2 - 7 [ 1cm]^2 ] =

pi [ 9 cm^2 - 7cm^2] =

2pi cm^2 ......this doesn't match any of the given answers......!!!!

[I tried to insert a picture of this but our image uploader isn't working]

Here's a pic of what you describe using Desmos.......https://www.desmos.com/calculator/cwrndrdb0x

CPhill Nov 30, 2015

#6**+5 **

2pi = Tau so it does match one answear. Thanks got stuck on this problem for quite a bit of time.

buubleman Nov 30, 2015

#7**+10 **

Best Answer

Thanks, buubleman.......I always thought that "tau" was just a variable.....I didn't realize it was associated with a numerical value.......you taught ME something, too!!!

CPhill Nov 30, 2015