Respuesta :
Given dimension of photograph = 25cm * 20cm
So area of photograph = 500cm²
Now, let the width of frame border be = x
So, dimensions of photograph + frame= (25 + 2x)*(20 + 2x)
As given, the area of frame is same as photograph , so
Area of picture + frame = 1000cm  ²
Hence, area equals
[tex]4x^{2}+90x+500=1000[/tex]
[tex]4x^{2}+90x-500=0[/tex]
[tex]2x^{2}+45x-250=0[/tex]
Solving this quadratic equation,
For the quadratic equation of the form [tex]ax^{2}+bx+c=0[/tex] , solution is:
x1,2 = [tex]\frac{-b+\sqrt{b^{2}-4ac}}{2a}[/tex]
Now putting a=2, b=45, c= -250 and solving he above equation, we get two values of x.
x = -27.11 (discard it as it is negative) Â and
x = 4.61 cm
Hence the dimensions of the frame are:
20+2x = 20+2(4.61) = 29.22 cm
25+2x = 25+2(4.61) = 34.22 cm
The width of the frame border is 4.61 cm.
What is an area
Area is the amount of space occupied by a two dimensional object or figure. For a rectangle:
Area = length * width
The length of the photograph be 25 cm and the width is 20 cm, hence:
Area = 20 * 25 = 500 cm²
Since the border is uniform, let w be the width hence:
500 + 500 = (25 + 2w)(20 + 2w)
w = 4.61 cm
The width of the frame border is 4.61 cm.
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