Area of a circle = d ^ 2 * pi / 4
Circumference of a circle = d * pi
Area of a rectangle = Circumference * height = d * pi * h
Area of a cylinder = 2 * Area of a circle + Area of a rectangle
A = 2 * d ^ 2 * pi / 4 + d * pi * h
So :
A = 2 * d ^ 2 * pi / 4 + d * pi * h =
d ^ 2 * pi / 2 + d * pi * h =
d * pi * ( d / 2 + h )
A = d * pi * ( d / 2 + h )
______________________________
Remark:
r = d / 2
A = d * pi * ( d / 2 + h ) is equivalent of:
A = 2 * r * pi * ( r + h )
____________________________
pi rounded to the nearest whole number = 3
1 in = 2.54 cm
1 ft = 12 in = 12 * 3.54 = 30.48 cm
6 ft = 6 * 30.48 = 182.88 cm
Now you can calculate the surface area of a cylinder
How to find the surface area of a cylinder with a diameter of 6ft and a height of 20cm using 3.14 rounded to the nearest whole number. (I cant figure it out my book doesn't give an example of it just a radius formula and ive tried searching the formula but i cant find any websites that show me how to do it or whats the formula) please help.
5 answers
Surface Area
A = 2•pi•r^2 + 2•pi•r•h
The radius is half the diameter
2(3.14)3^2 + 2(3.14)3•20
56.52 + 376.8 = 433.32
A = 433cm
A = 2•pi•r^2 + 2•pi•r•h
The radius is half the diameter
2(3.14)3^2 + 2(3.14)3•20
56.52 + 376.8 = 433.32
A = 433cm
Explanation
r = d / 2
d = 2 r
For that reason
A = d * pi * ( d / 2 + h ) =
2 * r * pi * ( r + h )
r = d / 2
d = 2 r
For that reason
A = d * pi * ( d / 2 + h ) =
2 * r * pi * ( r + h )
thank you guys I figured it out! and especially to Chelle (:.
omg just give the answer u retuards
11 answers