Calculating the surface area of a cylinder is easy once you understand the steps!
A cylinder is a shape with two circular ends and a curved side that goes around it. Here’s how to figure out its surface area:
First, you need to measure:
A cylinder has two round ends, so you have to find the area of one circle first. You can use this formula:
Area of one base = π r²
Since there are two bases, you multiply by 2:
Area of both bases = 2 π r²
Now, think of the curved side of the cylinder like a rectangle that wraps around it.
The width of this rectangle is the circle's circumference, which is how far you’d go around the circle. The height of the rectangle is the same as the height of the cylinder. You can find the circumference with this formula:
Circumference = 2 π r
Now, to find the curved surface area, you multiply the circumference by the height:
Curved Surface Area = Circumference × Height = 2 π r × h
To get the total surface area, you simply add the area of the two bases to the curved surface area:
Total Surface Area = Area of both bases + Curved Surface Area
So when you put it all together, you get:
Total Surface Area = 2 π r² + 2 π r h
In short, the formula for the surface area of a cylinder is:
Total Surface Area = 2 π r² + 2 π r h
Once you know this formula, it will be really helpful when you work on geometry problems about cylinders in 9th grade!
Calculating the surface area of a cylinder is easy once you understand the steps!
A cylinder is a shape with two circular ends and a curved side that goes around it. Here’s how to figure out its surface area:
First, you need to measure:
A cylinder has two round ends, so you have to find the area of one circle first. You can use this formula:
Area of one base = π r²
Since there are two bases, you multiply by 2:
Area of both bases = 2 π r²
Now, think of the curved side of the cylinder like a rectangle that wraps around it.
The width of this rectangle is the circle's circumference, which is how far you’d go around the circle. The height of the rectangle is the same as the height of the cylinder. You can find the circumference with this formula:
Circumference = 2 π r
Now, to find the curved surface area, you multiply the circumference by the height:
Curved Surface Area = Circumference × Height = 2 π r × h
To get the total surface area, you simply add the area of the two bases to the curved surface area:
Total Surface Area = Area of both bases + Curved Surface Area
So when you put it all together, you get:
Total Surface Area = 2 π r² + 2 π r h
In short, the formula for the surface area of a cylinder is:
Total Surface Area = 2 π r² + 2 π r h
Once you know this formula, it will be really helpful when you work on geometry problems about cylinders in 9th grade!