Photo:
THE MIRROR
Last week's puzzle was a really tough one.
The following puzzle falls into the "easy" category.
It shouldn't cause you any big problems.
Given is a five-pointed star.
Each vertex connects to two opposite vertices, dividing the star into five triangles and a pentagon - see drawing above.
Three angles are given.
Is that enough to calculate the size of the acute angle in the orange triangle?
How big is this angle?
The angle is
30 degrees
.
We can easily calculate the two missing interior angles in the green triangle.
The one on the left is 180 - 110 = 70 degrees.
And the one on the right is also 70 degrees because of the sum of the interior angles in the triangle of 180 degrees (180 - 40 - 70 = 70 degrees).
So we already know the upper angle in the orange triangle - the size is also 70 degrees, because both angles are so-called vertex angles.
We can also easily calculate the second angle of the orange triangle.
It is 80 degrees tall - see drawing below.
The angle we are looking for is therefore 180 - 70 - 80 = 30 degrees.
I discovered this easy geometry puzzle on Twitter from the @pickover account.
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