MHB Find Area Problem in Multiple Choice Question

[susanto3311]

hi all...

how to easy find to figure it out this problem..

how to find are that shading blue color..

please, see my picture..

thanks in advance...susanto3311

 

[I like Serena]

Hi susanto3311! :)

What is the area of a square with side 10?
And a circle with diameter 10?

 

[susanto3311]

Hi susanto3311! :)

What is the area of a square with side 10?
And a circle with diameter 10?

i don't understand what do you answer...

 

[I like Serena]

i don't understand what do you answer...

The blue area is the area of the square minus the area of the circle.

A square with side $s$ has area $s^2$.
A circle with diameter $d$ has area $\frac 1 4 \pi d^2$.

What would you get if you calculate those?

 

[susanto3311]

The blue area is the area of the square minus the area of the circle.

A square with side $s$ has area $s^2$.
A circle with diameter $d$ has area $\frac 1 4 \pi d^2$.

What would you get if you calculate those?

hi Serena...

Finally, with your formula my calculation the result is 21.5 cm2.
it's true? please, corrected if my answer is wrong...

thanks Serena...

 

[I like Serena]

hi Serena...

Finally, with your formula my calculation the result is 21.5 cm2.
it's true? please, corrected if my answer is wrong...

thanks Serena...

Yep. It's true. (Nod)