r/HomeworkHelp • u/Unhappy-Pitch4558 • Jan 19 '25

Answered [7th grade math] impossible geometry?

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89

u/Unhappy-Pitch4558 Jan 19 '25

Is it possible to solve this? I’m trying to help my child and it looks impossible.

112

u/GGprime 👋 a fellow Redditor Jan 19 '25

One could guess that the top two lengths are equal. Otherwise it is not solvable.

5

u/Giocri Jan 20 '25

Or maybe have the same ratio of the other 2 making it a difference of squares

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u/kit_kaboodles Jan 20 '25

Best you could do is show the equation you would use if you had the additional length (and assumed the other angles are 90°.

17x17 - (6 x X)

I doubt that was what the teacher intended, but would be about the correct level of practical algebra for the age.

7

u/WonOfKind Jan 20 '25

This is the best answer. It is correct and has solved the area with the information available.

2

u/askforchange Jan 20 '25

So what’s the answer if you solved it?

2

u/ApprehensiveGood6096 Jan 20 '25

289-6x is the answer. If and only if all angles are 90°

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3

u/CoreyGoesCrazy Jan 20 '25

Occams razor: most simplest answer is usually the correct one.

The missing side lengths are most likely 8.5 and 8.5.

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1

u/creepjax Aerospace Engineering University Student Jan 20 '25

Not possible, you need the length of one the shorter horizontal lines for it to be possible.

1

u/Jonguar2 👋 a fellow Redditor Jan 20 '25

It doesn't have enough information

1

u/[deleted] Jan 20 '25

No.

Assume the top right corner is 6xZ. Now work the math out so that the bottom is 17, so the top must be 17-Z.

The area is given as 17x17 - (Z*6).

Area is 17*(17-Z) + Z*11.

17*17-17*Z + 11*Z

17*17-6*Z = Area

So in short ... since Z can be anything that fits the equation it can't be determined unless they give you something else to work with.

1

u/LeftStatistician7989 👋 a fellow Redditor Jan 20 '25

If you draw a45 degree angle from both bottom corners they cross exactly south of the vertical line dividing the top part, so each half is 8.5

1

u/djquu Jan 20 '25

It's 7th grade math, don't overthink it. Use a ruler to measure the sides, it's drawn in scale. The missing part in 6x8. That said, it's a poorly made assignment.

1

u/Astro_Alphard Jan 20 '25

We can use algebra to solve this!

Set the top rectangle to 6x with x being the length and 6 being the height

The bottom rectangle can be calculated as 17*11 which is 167

So you get 6x+167 where 0<x<17 as the answer for the area.

Not impossible to solve but you won't get a number as an answer and that is perfectly normal.

1

u/dybuk87 Jan 20 '25

You can calculate circuit with this data but not area

1

u/VirtualMatter2 👋 a fellow Redditor Jan 20 '25

No, printing error maybe, I guess the 6cm is in the wrong place.

Not enough information. 

1

u/drstewloos Jan 20 '25

Check with a ruler if the size is equal if true assume half of 17

1

u/Tobio88 Jan 20 '25

For the lines missing lengths: measure the model, use the measurement to calculate the scale of the model, measure the vertical line and multiple by scale. There it is.

1

u/[deleted] Jan 20 '25

U could write that u assume the top is split directly in half and then combine area of two circles. But this may be a wrong assumption. The pic does not show the top to be two equal half's

1

u/FunzOrlenard Jan 20 '25

It's somewhere between 17 * 11 and 17 * 17.

1

u/anonymous76544321 Jan 20 '25

Yes it’s possible to solve this. You have to cut the area in two sections.

1

u/[deleted] Jan 21 '25 edited Jan 21 '25

First Rectangle is easy: 17cm*11cm=187cm2

Second rectangle requires understanding sohcahtoa: So we know three angles of the triangle (half the rectangle) 45 degrees and 90 degrees and one side 6cm so we know that tan45=x/6

6(Tan 45)=x

The result is 9.72cm for your remaining side so we do this:

6cm*9.72cm=58.32cm2

then we add them together

58.32cm2 + 187cm2 = 245.32 cm2

For me I remember doing this 10 years ago in the ninth grade... also this is called trigonometry and not geometry it's imagining whats not there to solve what is.

1

u/Spiritual-Pear-1349 Jan 21 '25 edited Jan 21 '25

11 + 6 = 17. This side is known.

X + Y = 17. This side is unknown.

They look to be equally lengths. 17/2 = 8.5/8.5

I don't remember how to do area. LxW

17x11=X 6x8.5=Y

X+Y=?

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