SOLUTION: A square and an equilateral triangle have the same height. The square has an area of 225 feet squared. What is the area of the triangle?

Algebra ->  Triangles -> SOLUTION: A square and an equilateral triangle have the same height. The square has an area of 225 feet squared. What is the area of the triangle?       Log On


   



Question 823933: A square and an equilateral triangle have the same height. The square has an area of 225 feet squared. What is the area of the triangle?

Answer by TimothyLamb(4379) About Me  (Show Source):
You can put this solution on YOUR website!
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square:
a = 225 = xx
x = 15
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triangle:
h = 15
s = sqrt( 15*15 + (s/2)(s/2) )
ss = 225 + ss/4
ss - ss/4 - 225 = 0
4ss/4 - ss/4 - 225 = 0
3ss/4 - 225 = 0
0.75ss - 225 = 0
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the above quadratic equation is in standard form, with a=0.75, b=0, and c=-225
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to solve the quadratic equation, by using the quadratic formula, copy and paste this:
0.75 0 -225
into this solver: https://sooeet.com/math/quadratic-equation-solver.php
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this quadratic has two real roots (the x-intercepts), which are:
s = 17.3205081
s = -17.3205081
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negative length doesn't make sense for this problem, so use the positive root:
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answer:
triangle side = 17.3205081 ft
triangle area = 1/2(17.3205081)(15) = 129.9 sq.ft
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Solve quadratic equations, quadratic formula:
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