Three Cuts to Turn a Round Cake Into Eight Equal Slices

How can you cut a round cake three times to make eight equal slices?

Cut #1 – Down the center of the cake (vertically) leaving two equal halves.
Cut #2 – Across the center of the cake (horizontally) leaving four equal slices.
Cut #3 – Through the middle edge of the cake slicing all four of the pieces in equal halves, leaving eight equal slices (four equal tops and four equal bottoms).

Posted in Brain Teasers

30 Comments on "Three Cuts to Turn a Round Cake Into Eight Equal Slices"

Rashmikant Shah says
May 25, 2014 @ 14:47

First cut makes Two circles (inner circle will have 2/3 radius) and two more cuts perpendicular to each other will result in 8 equal pieces

Rashmikant Shah says
May 26, 2014 @ 11:42

First cut makes TWO halves. Place both halves one above another and make a cut making FOUR pieces. Place these four pieces one above other and cut them to make EIGHT equal size pieces.

crazy says
May 26, 2014 @ 13:34

It is really four not three. I tried it and it was four

It only takes three cuts.

Rahul lamba says
October 7, 2014 @ 01:28

The “correct” answer is to cut the cake in quarters (4 pieces) using 2 of the cuts – one horizontally down the center of the cake and the other vertically down the center of the cake. This will leave you with 4 pieces (or slices) of cake. Then, you can take all 4 pieces and arrange them in a stack that is 4 pieces high. Finally, you can just cut that stack of 4 pieces in half – using your third and final cut – and then you will end up with 8 pieces of cake!

StrayzGamer says
October 22, 2014 @ 16:22

You could think it as a donut with the hole filled in, so when you make a slice down the middle and two on the left and right going vertically, you have 8 slices because the hole is filled in. :)

Celia says
May 14, 2015 @ 15:22

Cut it vertically, then horizontally, then through the middle.

Ciel Takuro Yuki says
July 8, 2015 @ 10:03

neat

cut master says
August 5, 2015 @ 12:45

It is so easy guys

Bonnie says
February 13, 2016 @ 17:38

No need for cake stacking or cutting circles out of circles. Think of the cake as a cylinder. Slice the cylinder into quarters as you normally would cut a cake. Then, slice the cylinder into two cylinders by making a cut halfway between the top and bottom of the cake. You’re left with eight pieces of cake, all in the shape of a quarter circle half as tall as the original cake was.

Gemini says
March 31, 2016 @ 20:42

OK OK I think I got it.?

Yasmin says
May 5, 2016 @ 04:55

Thanks guys, this is my homework lol???

kjs68 says
May 10, 2016 @ 21:20

Really? Slow thinkers? First. If you cut a 2 layer cake with icing on it, horizontally through the middle, the result is icing on the top 4 pieces and no icing on the bottom four. Not a fair shake for the last four cake eaters.

Rocky says
June 6, 2016 @ 05:49

open your mouth and get these sliced cakes in your mouth and just shut up

shanky says
June 29, 2016 @ 08:33

Bonnie should provide the video to explain it.

Danny says
July 28, 2016 @ 11:53

But what if it’s a Victoria sponge cake or any other type of cake with a messy middle?

Then…you would have a mess? :)

confused says
March 13, 2017 @ 21:01

I dint understand at all like how does that work? it 4 if u really think about it…

Kent says
March 22, 2017 @ 09:42

Could you supply a cut by cut diagram. Most seem confused.

Chase says
April 5, 2017 @ 18:28

The first person has the most elegant answer, but his math is incorrect. The first cut is a circle within the cake with a radius that is the radius of the whole cake divided by the square root of 2. Then the next 2 cuts are horizontal down the entire cake and vertical through the entire cake. This produces a circle within the circle that is divided into 4 pieces, and an outer ring around that circle that has 4 pieces that are the same size as the 4 within the inner circle. Not easy, but not too tough

Billk says
May 1, 2017 @ 17:28

“Splitting the layers” with the third cut requires the “round cake” be flat on top. To an extent, so does stacking the quarters to halve them. However, they can be lined up and halved no matter what the top looks like.

Gen_DEVO says
November 5, 2017 @ 18:55

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jyoti says
August 14, 2018 @ 12:12

cut the cake into two equal semicircles using one line, place one piece over the other and then cut the whole into 4 parts, as a result, total parts will become 8.

Versha Agarwal says
October 13, 2018 @ 16:23

First cut the cake into four equal pieces. Now you are left with only one cut.Be SMART. Now cut yhe cake as you are drawing a inner circle in a cake. Now you are done with three cuts and also having 8 cuts.
4 equal to others and another 4 equal to each other.

sahil raj says
March 14, 2019 @ 17:48

cut cake from center (semicircle) then place one above another then cut it , it gives 4 pieces then put all 4 pieces one above another then put final cut in between . then it will give total and equal 8 cuts in 3 steps.

Hello hello hello hello,? says
April 17, 2019 @ 10:10

One vertically one horizontally and one through the middle edge of the cake slicing all four of the pieces in equal halves, leaving eight equal slices, some on the top and bottom.

May 3, 2019 @ 07:38

The guy is saying that u cut the circle in halve twice, now you have four equal slices. The last one makes the cake a two layer cake, it’s through the middle of the cake height-wise!

Arrghdale says
May 9, 2019 @ 15:11

Wrong – the lower slices will not have icing on the top so not equal :-)

Bhanu krishna says
May 25, 2019 @ 11:52

Cut the cake in to 1.semi circle
2. Put half cake on the other -then slice it in half_4 pieces
3.put two halfs on to other – then cut it down_will get 8 pieces

1.= 1/2
2.= 2/4
3.= 4/8
?☺️?

Filippo Pincelli says
February 3, 2023 @ 06:59

A pie not only has a radius, it also has a height, h.
1st cut: divide the cake into 2 cylinders one above the other by cutting halfway up the cake and so that the cutting plane is parallel to the top surface of the cake. Leave the 2 cylinders of height h/2 one above the other. Now from the top make 2 orthogonal cuts that cut both the top and bottom cylinder.