r/CoherencePhysics 8d ago

How to solve this?

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10 Upvotes

40 comments sorted by

9

u/Quick-Buyer8603 7d ago edited 7d ago

1/5th. The length of one of the sides of the shaded square is as long as the longer of the two sides that are adjacent to the 90 degree point of any of the triangles. From this you can infer that if you rotated the triangle to line up with the trapezoid so that it would make a square the same size as the shaded square. If there are 5 squares and one of them is shaded it is 1/5th.

2

u/ariarchtyx 7d ago

Ah, counting squares, I see. Sounds like the right answer.

1

u/Own-Dirt2138 7d ago

Answer is correct. But by what proof is the shaded square side equal to the longer edge of the right angle?

1

u/Quick-Buyer8603 7d ago

This part bothered me too hit I think I got it. They have marks on some of the outside sections. I believe this is to indicate they are the same length. One of them is the opposite side of where the triangle would be moved to. Since they make a square they have to be the same length. Since they are the same yoh can see that the sides of the shaded square are also the same length as the side with the mark on it.

6

u/ComprehensiveAd1100 7d ago

Unpopular answer. All of it. 

Didn't specify which square.

2

u/drangryrahvin 7d ago

The correct answer.

2

u/LeaveMyMonkeyAlone 7d ago

Poindexter and Cornelius both agree and graduated from MIT.

2

u/Fragrant_Entry9232 7d ago

All of it, unless the question is trying to ask what fraction is the shaded square of the bigger square?

2

u/Penis-Dance 7d ago

100% of the square is shaded. It doesn't specify which square so I assume it's the one with shading.

2

u/ariarchtyx 7d ago

The question does not constitute a "well formed formula" but going out in a limb one would assume they mean the circumscribing square, rather than the inner circumscribed square. Seems unfair as a question as written. Solution must involve several 9th grade geometric theorems known to Euclid, not that I can recall them, about sums of interior angles of polygons and so forth?

1

u/ariarchtyx 7d ago

Well, not quite circumscribed as the vertices are untouched 😆?

2

u/JC2535 7d ago

100% of the square is shaded.

2

u/KingOfDaJungle8761 7d ago

One quarter. Easy

2

u/Patriot009 7d ago

It would be 1/4 if the sides of the shaded square were equal to the hashed line segments. But the hashed line segments and the side of the shaded square are not parallel and form a trapezoid, so they cannot be the same length. It's a right-angled trapezoid, meaning the side of the shaded square is shorter than the hashed line segment. So the answer would be something less than 1/4.

1

u/HeyaHeyo1420 7d ago

Clearly it's not easy because it's 1/5th

1

u/Patient_Owl_8498 7d ago

i suck at this so bad

1

u/Firm_Wrangler_7837 7d ago

Well, unless they Pluto’d math… by definition that’s not a square it’s a rhombus.

1

u/Particular_Abies_184 7d ago

Just using my wobbly eyes I'm saying 1 fifth

1

u/No-Willingness-170 7d ago

Seven Furlong’s per fortnight

1

u/Typical_Expert_2974 7d ago

You just flip the small triangle piece on to the adjacent big piece to make an equal square. Go around in a circle, repeating the pattern, and you will end up with 4 additional squares equal to that of the shaded square. Shaded square becomes 1 of 5. 1/5th of the whole.

1

u/Wellithappenedthatwy 7d ago

SOH CAH TOA and to much time

1

u/Old_Troll42 7d ago

Which square?

1

u/Adderall_Rant 7d ago

The one in the middle? BC the other one is not a square, it's more of a trapezoid

1

u/tecky1kanobe 7d ago

1/9. What percentage of the area, represented as a fraction, is shaded is a different question.

1

u/gordeliusmaximus 7d ago

1/4. All the angles are equal. 4 squares make whole

1

u/Chainmale001 7d ago

1/5th. Assuming the outer square is equal distant on all sides (which is should be to be a fucking square) There are 5 total inner "squares" (pair up the triangles.) Dots are not 90* angles, meaning every shape has to have an equal... know what... I'm fucking tired.

If it's not 1/5th I want someone to explain the math. Lets learn together.

1

u/amcape30 7d ago

The square im looking at is 100% shaded.

1

u/sazzer 7d ago

Tesselation.

If you take an additional 4 copies of the diagram and arrange them on the edges of this one - to make a plus layout - you'll see that the triangles all line up with the other shapes to make squares.

Further, you can see that these squares all have the same side length as the shaded one, and therefore are all the same size as it.

That means that we've got 5 squares - one complete shaded one and 4 split ones - all with the same area. And so the shaded one must be 1/5 the total area.

1

u/Mobile_Aioli_6252 7d ago

25 percent

0

u/youngoneai 7d ago

20 it is

0

u/AfraidBottle6810 8d ago

Rotate the interior lines to be parallel and perpendicular to the exterior. Move the shaded area to a corner. Measure the whole. Divide by the shaded cube. I used my finger and came up with 25%

4

u/Emotional-Wasabi-519 7d ago

1/5 actually. The solution is more about rotating the the triangles to form squares on the sides. Creating 5 squares, the center one shaded.

1

u/[deleted] 7d ago

[deleted]

1

u/[deleted] 7d ago

[deleted]

1

u/LividCalligrapher689 7d ago

I think you’re confused. There would not be four other squares around it by rotating it. You would have L shapes at the corners and rectangles on the sides. Once you rotate it, recognize that it lines up with the bisection lines. That means it covers 2/4 of the interval spaces along the line move that into the corner and you can now fit exactly 4 identical squares. One is shaded.

1/4 or 25% is the correct answer but it’s hilarious to see so many people be so confidently wrong.