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BrainTwister #19: Angular arrangements

Can you solve this week’s logic puzzle? Plus our quick quiz and the answer to last week’s problem

By Alison Kiddle

8 May 2024

New Scientist. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine.

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#19 Angular arrangements

Set by Alison Kiddle

A regular polygon is a shape with at least three straight sides where all the sides are the same length and all the interior angles are equal.

New Scientist. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine.

Knowing that a full turn is 360° and the angles in a triangle add up to 180°, can you use this diagram to work out the size of the interior angles in this regular pentagon? Hint: an interior angle is made up of two adjacent angles from the outer corners of the triangle.

Can you use the same idea to find a general way to calculate…

Article amended on 15 May 2024

The solution to BrainTwister #18, The arithmetical two-step, was corrected.

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