# What percentage of blue? [closed]

Lines are drawn parallel to the base of the triangle, dividing the other sides into 10 equal parts.

Every second strip is painted blue.

Question

What is the percentage of blue color in the triangle?

## closed as off-topic by Rand al'Thor, greenturtle3141, gabbo1092, Sconibulus, Peregrine RookJun 24 at 21:23

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "This question is off-topic as it appears to be a mathematics problem, as opposed to a mathematical puzzle. For more info, see "Are math-textbook-style problems on topic?" on meta." – Rand al'Thor, greenturtle3141, gabbo1092, Sconibulus, Peregrine Rook
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If you draw parallel lines to the left side of the triangle, you see that parallelograms and half parallelograms arise. On each ten segments divided by the red lines, you see that there is always one half white parallelogram more than the blue parallelograms. So there are 10 half white parallelograms more than black. Also you can see that each strip contains a number of these half parallelograms.

Total number of triangles:

$$sum(2*n-1) = 100$$, n starts at strip 1 and goes to strip 10.

w : white half parallelograms

b : blue half parallelograms

b + w = 100,
w = b + 10,
2 * b + 10 = 100,
b = 45

So...

45/100 = 45%

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