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Answer:
36√3 cm
Step-by-step explanation:
The perimeter of an equilateral triangle is 2√3 times the height.
P = (2√3)h
P = (2√3)(18 cm) = 36√3 cm
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A little more detail
The hypotenuse of a 30°-60°-90° triangle is 2/√3 times the longer leg. Here, the longer leg is 18 cm, so the side length of the equilateral triangle is ...
18(2/√3) = 12√3 . . . cm
The equilateral triangle perimeter is 3 times that, or 36√3 cm.
