Find the area of the shaded region

Question

anonymous · Answer

attachment

raden · Answer

it is like a rhombus
the formula to get area of a rhombus is
area = 1/2 * d1 * d2

anonymous · Answer

find the area of the whole big outer square first, which is A=9x9=81.
then find the area of a triangle. once you find that area multiply it by 4. that total area would then need to be subtracted by the first area we found of the bigger square. then thats your answer.

anonymous · Answer

Okay......

anonymous · Answer

fitsr get the side of the square by using pythagoras theorem
$$\Large hyp=\sqrt{3^2+9^2}=\sqrt{90}$$

multiply the two sides to get answer.

anonymous · Answer

youre welcome...........

raden · Answer

here, d1=d2=9

anonymous · Answer

haha thanks @zxcv1234  i just still didnt know what to do

anonymous · Answer

Okay, yeah I get you prob broke this down a lot to explain but can you break it down a little more?

anonymous · Answer

yes, do you agree that in order to find the area of the shaded region, you have to find the area of the bigger square first, then subtract it by the 4 triangles?

anonymous · Answer

yes

anonymous · Answer

ok so find the area of that first

anonymous · Answer

and you said that was 91

anonymous · Answer

ha just kidding you said it was 81

anonymous · Answer

did you know how i got that

anonymous · Answer

well you said it was 9x9 the length times the width

raden · Answer

oppss.. im mistake, ur pic lies my eyes :)
it should d1=d2=3sqrt(10)
so, area = 1/2 * 3sqrt(10) * 3sqrt(10)

anonymous · Answer

good. now find the area of the triangle