Answer:
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Step-by-step explanation:
difference of a number and 9 means to subtract
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twice that means multiply by 2
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at least is greater than or equal to
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I believe 900 meters your welcomes
Equilateral triangle is a triangle with the 3 sides of the same length, and the 3 angles with the same measures/degree.
The formula to find the area of a triangle is base x height/2 , you do have the base (40), but you need the height. To find the height of an equilateral triangle you use the formula: side/2 x radical3, this way u'll find the height and therefor can calculate the area of the triangle.
Hope that helped :)