Volume of a rectangular prism is given by the
formula:
Volume = (Area of the rectangular cross
section)*Height
substituting given values of height and
volume in the above formula:
30 = (Area of the rectangular
cross
section)*3
Therefore:
Area of
the rectangular cross section = 30/3 = 10 cm^2
Let lengths
of two side of the triangle be x and
y
Then:
Area of rectangle =
x*y = 10
Therefore:
y =
10/x
And:
Perimeter of the
rectangle = 2*(x + y) = 14
==> x + y =
7
Substituting values of y as 10/x in above
equation:
x + 10/x =
7
Multiplying both sides by x, and shifting all the terms
of equation on left hand side:
x^2 - 7x + 10 =
0
==> x^2 - 2x - 5x + 10 =
0
==> x(x - 2) - 5(x - 2) =
0
==> (x - 2)(x - 5) =
0
Therefore:
x = 2 or
5
Therefore sides of the rectangular prism are 2 cm and 5
cm.
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