Question
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.
Answers
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
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
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
Related Questions
The surface area of a right circular cylinder is 1200 cm^2 . If the height of the cylinder is twice...
Find the surface area of the cylinder. Use the approximation of 3.14 for pi. The height of the cylin...
The diameter of the base of a cylinder is 1.4 m. The height of the cylinder is 0.6 m. Find the exact...