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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.
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.
