Question

How do you cut a circular birthday cake in 8 equal pieces in exactly 3 cuts

Answer 1

First cut : Cut the cake from between. So it looks like u hv two cakes which are half the size (height) of the original one.

Keep these two pieces on each other. Do not keep them separately. 

Second cut: Cut the diameter of the cake ( vertically)  into two halves. So now we have four pieces. 

Third cut: Cut the cake diameter again but this time horizontally. 

Now u have eight pieces each of same size.

Answer 2

we can make 8 equal pieces by 3 cuts only.

1cut = A horizontal cut at the middle of the cake . This will divede the cake into 2 equal pieces.

2 cut = transverse cut from top of the cake. This will divide the cake into 4 equal pieces.

3 cut = again a transverse cut at 90 degrees from the 2 one. This will divide the cake into 8 equal pieces

Hope you like this answer.