BdMO National 2021 Primary Category Problem 9

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Anindya Biswas
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BdMO National 2021 Primary Category Problem 9

Unread post by Anindya Biswas » Mon Apr 12, 2021 10:19 pm

কোনো একটা আকৃতির পরিসীমা হলো তার বাউন্ডারির দৈর্ঘ্য। যেমন কোনো একটা ত্রিভুজের পরিসীমা হলো তার তিনটা বাহুর দৈর্ঘ্যের যোগফল। নিচের ছবিতে $ABC$ আর $DEF$ দুটোই সমবাহু ত্রিভুজ এবং $BC$ আর $DE$ বাহুদুটো সমান্তরাল। $\triangle ABC$ আর $\triangle DEF$-এর পরিসীমা যথাক্রমে $12$ আর $15$। ছায়াকৃত অংশের পরিসীমা কত?

The perimeter of a shape is the length of the boundary surrounding that shape. For example, the perimeter of a triangle is the sum of all its three side lengths. In the following diagram, $ABC$ and $DEF$ are both equilateral triangles and the sides $BC$ and $DE$ are parallel. The perimeters of $\triangle ABC$ and $\triangle DEF$ are $12$ and $15$ respectively. What is the perimeter of the shaded region?
P9-nat2021.png (14.67 KiB) Viewed 341 times
"If people do not believe that mathematics is simple, it is only because they do not realize how complicated life is."
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Swapnil Barua
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Re: BdMO National 2021 Primary Category Problem 9

Unread post by Swapnil Barua » Mon Apr 26, 2021 10:30 pm

DEF triangles DF segment has the equal length of the shaded regions 3 segments and other 3 segments has the equal length of ABC triangles AC segment
Shaded regions perimeter = $\frac{12}{3}$ + $\frac{15}{3}$ = 9

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