$$PQRS$$ is a square whose side is $$20 cm$$. By joining opposite vertices of $$PQRS$$ are get four triangles. What is the sum of the perimeters of the four triangles?
Side of square is 20 cm.
So, diagonal of square is 20√2 cm.
So,to calculate perimeter of triangle,we get to count each diagonal 2 times and 4 sides only one time .
So, required perimeter=4×20+4×20√2
=(80+80√2) cm.
B is correct choice.
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