Let
x------> the length side of the square base of the box
y-------> the height of the box
we know that
volume of the box=b²*h
b=x
h=y
volume=256 cm³
so
256=x²*y------>y=256/x²--------> equation 1
<span>The amount of material used is directly proportional to the surface area, so we will minimize the amount of material by minimizing the surface area.</span>
surface area of the cardboard=area of the base+perimeter of base*height
area of the base=x²
perimeter of the base=4*x
height=y
surface area=x²+4x*y-----> equation 2
substitute equation 1 in equation 2
SA=x²+4x*[256/x²]-----> SA=x²+1024/x
step 1
find the first derivative of SA and equate to zero
2x+1024*(-1)/x²=0------> 2x=1024/x²----> x³=512--------> x=8 cm
y=256/x²------> y=256/8²-----> y=4 cm
the answer is
the length side of the square base of the box is 8 cm
the height of the box is 4 cm
First set up the equation (sum of the angles is 180)
2x + 2(x-1) + (5x +2) = 180
distribute:
2x + 2x -2 + 5x +2 = 180
combine like terms:
9x = 180
solve for x:
x = 20
SO:
2x° = 2(20) = 40 degrees
2(x-1)° = 2(20) - 2 = 40 - 2 = 38 degrees
5x + 2°= 5(20) + 2 = 100 + 2=102 degrees
check: 40 + 38 + 102 = 180
Answer:
x = 7
Step-by-step explanation:
x + 7 = 14
Subtract 7 from both sides
x = 14 - 7 = 7
Divide 90 by 1.3 and you will get your answer.
Do it yourself! just follow instructions!
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