Answer:
D
Step-by-step explanation:
surface area of cylinder
=(area of base)×2 + (area of curved surface)
× 2 + 
× 25
=2 × 
× 
+ 2 × × 10 × 25
6 feet is longer because 6 feet = 72 inchs
and because 70 feet = 5.83333
Answer:
Let the number be x
Given:
11 + 5x = 20 + 2x
5x - 2x = 20 - 11
3x = 9
x = 3
The number is 3.
Step-by-step explanation:
Answer:
h /r = 2.55
Step-by-step explanation:
Area of a can:
Total area of the can = area of (top + bottom) + lateral area
lateral area 2πrh without waste
area of base (considering that you use 2r square) is 4r²
area of bottom ( for same reason ) 4r²
Then Total area = 8r² + 2πrh
Now can volume is 1000 = πr²h h = 1000/πr²
And A(r) = 8r² + 2πr(1000)/πr²
A(r) = 8r² + 2000/r
Taking derivatives both sides
A´(r) = 16 r - 2000/r²
If A´(r) = 0 16 r - 2000/r² = 0
(16r³ - 2000)/ r² = 0 16r³ - 2000 = 0
r³ = 125
r = 5 cm and h = ( 1000)/ πr² h = 1000/ 3.14* 25
h = 12,74 cm
ratio h /r = 12.74/5 h /r = 2.55
