Question

A long wire of 20m was cut into two pieces ? If the length of one piece is 36/5. Find the length of the other piece. *

1 point

A) 64/5

B) 10/5

C) 20/5

D) 56/5

​

Answer 1

ANSWER

Let the 2 pieces be x,y

Given,

     x+y=20

Perimeter of square =x

Side=  4 x

​Area of square =  16 x  2

 Perimeter of triangle =y

Side=  3 y

​Area of triangle =  4 3  (  3 y  )  2  =  36 3  y2

 z= area of square + area of triangle

z=  16 x 2 +  36 3 y2

z=  16 x  2   +  36 3  (20−x)2

differentiating the equation, we get,

dx dz =  8 x  −  18 3  (20−x)

​  equate,  dx dz =0

we have,

8 x  −  18 3  (20−x)  =0

8 x  =  18 3 (20−x)

​  solving the above equation, we get,

→x=  (9+43  ) 803

​y=20−  (9+43  ) 803

​→y=  (9+43 )180 dx2d  2

z  =  8 1  +  18 3  >0

Thus z is minimum, when x= (9+43 )

80 3

and y= (9+43 ) 180

​ Hence, wire of length 20cm should be cut into pieces of lengths  (9+4 )803

​  (9+4 3 ) 180 m

Answer 2

Step-by-step explanation:

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