The selling price of an item is $585. It is marked down by 20%, but this sale price is still marked up from the cost of $360.
2 answers:
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Answer:
Step-by-step explanation:
The area of a triangle is given by
where
b is the base
h is the height
Here we have an equilateral triangle, which has the 3 sides of the same length.
Let's call L the length of one side.
We know that the perimeter of the triangle is
p = 9 in
The perimeter is the sum of the three sides, so:
Therefore, we find the length of the side:
Therefore the length is the base of the triangle,
The height can be calculated by considering half triangle: the hypothenuse is equal to L, while one side is equal to half the base (b/2), therefore the height is given by Pythagorean's theorem:
Therefore, the area of the triangle is: