Given δabc, ab = bc = ac . area of δabc = 25 sqrt3 /4 cm. find the perimeter of δabc.

This is an equilateral triangle of height a√3/2 where a is the side length. So the area is ½a.a√3/2=a²√3/4.
So a²=25 and a=5cm. Therefore the perimeter is 3a=15cm.

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