The surface area of a cylindrical can is equal to the sum of the area of two circles and the body of the cylinder: 2πr2 + 2πrh. volume is equal to π<span>r2h.
V = </span>π<span>r2h = 128 pi
r2h = 128
h = 128/r2
A = </span><span>2πr2 + 2πrh
</span>A = 2πr2 + 2πr*(<span>128/r2)
</span>A = 2πr2 + 256 <span>π / r
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the optimum dimensions is determined by taking the first derivative and equating to zero.
dA = 4 </span>πr - 256 <span>π /r2 = 0
r = 4 cm
h = 8 cm
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#1 There is no area of a cube. There is only a volume.
#2 The formula is

where s is the side.
Substitute 729 in V since that is the volume.

Take the cube root and you will get
9.
So the formula is
and the side is 9.
Add the two angles and then subtract from 180* to find the missing angle
So,
145* + 15* = 160*
180* - 160* = 20*
Answer: x = 20*
Here are the answers.
6. 63/100
7. 75/100 = 3/4
8. 91/100
9. 18/100 = 9/50
10. 3/100
11. 25/100 = 1/4
12. 5/100 = 1/20
13. 16/100 = 4/25
14. 1/100
15. 79/100
16. 40/100 or 4/10 = 2/5
17. 99/100
18. 30/100 or 3/10 = 3/10
19. 15/100 = 3/20
20. 84/100 = 21/25
I hope you find this answer the most helpful! :)