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Can you solve this 50 cent math exam question that has the internet divided?

High school students have been complaining that the exam question is too difficult

Web Desk November 04, 2015

PHOTO: INDEPENDENT

A multiple-choice math exam question about a 50 cent piece has confused several and sparked a debate online.

The question given to Year 12 Further Mathematics students in their Victorian Certificate of Education (VCE) exam in Australia, asked for the degree of an angle between two 12-side coins.

"A 50 cent coin has 12 sides of equal length. Two 50 cent coins are balanced next to each other on a table so they meet along one edge," the question reads.

Students were asked to find the degree of x in the middle, giving them options ranking from 12 degrees to 72 degrees.

Unable to figure out the answer, some students shared their confusion on social media, hoping to find help in solving the problem.

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One student frustratingly posted on Facebook, “That exam wasn't there to test us, it was to trick, no one could have prepared for that.”

Another claimed, “The 50 cent coin question makes no sense to me as it asked us to find the angle, but it gave us no other angles or lengths to enter in the formulas so there was simply no way about it.”

However, some people, baffled by the confusion of these students over the ‘easy question’, took to Twitter to share their opinion.

Well, as a Maths Methods, not a Further Maths student this was a cinch, but I get why people are getting stumped https://t.co/SQIcQDAtin
— Angela (@Angelayang) November 2, 2015

Are kids really this stupid these days? https://t.co/Z1PNDkzqK5
— Ed Trinh (@ed_trinh) November 2, 2015

https://twitter.com/JamColley/status/661121411742720000?ref_src=twsrc%5Etfw

According to local news site, The Age, teacher Graeme Newman described the question as ‘challenging’, but ‘fair’. He told the site, “Most exam questions try to give students a bit of a ‘kick along’ in terms of the way they set up the diagrams. They didn't do that in this question, they really needed to draw the triangles themselves and work it out from there.”

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How to work out the answer:

The answer to the question is 60 degrees. There are different ways to come to the correct solution. Here is one of them:

1) Calculate the sum of the interior angles of the coin. The formula for this is (Number of sides x 180) – 360, so the sum of the interior angles of the 12-sided coin is (12x180)-360=1800.

2) The coin is a regular 12-sided polygon, so all its internal angles are equal. To find the value of one internal angle, divide the sum of interior angles by the number of sides, so 1800/12=150.

3) A full circle is divided into 360 degrees. In the question the angle θ comprises part of a circle along with one internal angle from each of the coins. As one internal angle is 150 degrees, the two adjacent angles add up to 300 degrees, leaving θ with a value of 360-300=60 degrees.

This article originally appeared on Independent.

COMMENTS (14)

Fernando Bueno | 9 years ago | Reply I do 360/12 = 30 * 360/180 = 60

Fernando Bueno | 9 years ago | Reply ((360/12)*360)/180 = 60

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Amer | 9 years ago | Reply I didn't draw or write anything at all and came up with the answer after a few seconds of looking and thinking about it but I can see how people would get confused.

Akond of Swat | 9 years ago | Reply The equilateral triangle exponents will still have to prove that the triangle formed by completing the the base opposite angle x is not just isosceles but equilateral. The proof by the interior angles of the polygon or the vertex angles of the triangles sharing a common vertex at the centre of the regular dodecagon seems to be easier to prove and logical; avoiding possible unproved assumptions. However, if the equilateral nature of triangle containing x is easily proved, I would stand corrected.

Ali | 9 years ago | Reply Yes, a lot of people are stumped but Pakistanis who have never invented anything are claiming to have solved this in less than a minute. smh

Noman | 9 years ago | Reply Draw a line just below the 'x' will make it an equilateral triangle. Means 60 degrees each side.

Munir | 9 years ago | Reply Done in 60 seconds.

Saeedlala | 9 years ago | Reply I calculated it correctly without knowing the logic behind my calculation. A circle has 360 Degrees. Each of the 12 edges polygon has also 360 degree. Divide 360 by 12. On each side you get 30. Since they are two polygons, so 30+30 is 60.

Haris | 9 years ago | Reply Easier method, the most practical solution is that as all sides of the polygon are equal, and two sides that meet, using pythogoras theorem you can deduce that the triangle that forms is an equilateral triangle, and in an equilateral triangle all angles are 60 degrees.

Karachiite | 9 years ago | Reply this is 8th grade maths if im not wrong. the coin has 12 sides meaning the sum of its interior angles is (n-2)180 --> (12-2)180=1800. so each angle of the coin is 1800/12=150 degree. now if we drop a perpendicular from the lower common vertex of the 2 coins, the angle formed by each coin with this perpendicular will be 180-150=30 degree. if we add these we get 30+30= 60 degrees. problem solved :)

Reality Check | 9 years ago | Reply The simplest way is divide 360/12 and you get value of degree shift for each side that would be 30 degrees. Since two sidea are there multiply by 2 and u have the answer 60 degrees.

Omair | 9 years ago | Reply sum of exterior angles of a polygon is 360. 360/12 times 2...

Aadhaar | 9 years ago | Reply The best way is to divide the coin into 12 triangles, the smaller angle of all triangles will be 30 degree and other two angles remaining will be 75%. Add two angles and subtract it from 180 to get the outer angle. It comes to 30 degree make it twice u got the answer. I have no idea why this simplest of questions makes people wonder.

Aadhaar | 9 years ago | Reply It barely took 60 seconds and 1sq inch of paper to answer it, whats so difficult in this? if that x is little down it still will be easy.

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