How to Find Surface Area of a Cylinder: A Step-by-Step Guide

Learn how to find surface area of a cylinder using a step-by-step guide with real-world examples and visual aids. Understand the relationship between surface area and volume, and discover the applications of finding surface area of a cylinder in different industries.

Introduction

When it comes to finding the surface area of three-dimensional objects, the cylinder is one of the most common shapes encountered. From cans to pipes and tubes, cylindrical objects are everywhere around us. Knowing how to calculate the surface area of a cylinder is crucial in industries like manufacturing, construction, and engineering. In this article, we’ll explain how to find surface area of a cylinder using a step-by-step guide, real-world examples, visual aids, and practice problems.

How to Find the Surface Area of a Cylinder

The formula for finding surface area of a cylinder is:

Surface Area = 2πr² + 2πrh

Where:

r is the radius of the cylinder
h is the height of the cylinder
π is a mathematical constant that approximates to 3.14

Here is a step-by-step guide on how to use this formula:

Identify the radius and height of the cylinder.
Plug these values into the formula.
Simplify the expression using the order of operations (parentheses, exponents, multiplication, division, addition, subtraction).
Calculate the final numerical value of the surface area in square units.

Let’s take an example to understand this better.

Real-world Examples

Suppose you need to find the surface area of a cylindrical can of soup. The diameter of the can is 4 inches, and the height of the can is 5 inches. Here’s how you can find its surface area:

Identify the radius and height of the can.
- The radius of the can is half of its diameter. So, radius = 2 inches.
- The height of the can is 5 inches.
Plug these values into the formula.
Surface Area = 2π(2)² + 2π(2 x 5)
Simplify the expression using the order of operations.
Surface Area = 2π(4) + 2π(10)

Surface Area = 8π + 20π

Surface Area = 28π
Calculate the final numerical value of the surface area in square inches.
Surface Area ≈ 87.9646 in²

You can use a similar process to find the surface area of any cylindrical object with a known height and radius. Some other examples include tubes, pipes, and drums.

Visual Aids

While the formula for finding surface area of a cylinder may seem straightforward, it can be challenging for some learners to grasp the concept visually. That’s why it’s helpful to use diagrams, graphs, and tables for better understanding.

Here’s a table that compares different surface areas of cylinders with different heights and radii:

Radius (r)	Height (h)	Surface Area (SA)
2 in	4 in	50.2655 in²
3 in	5 in	94.2478 in²
5 in	8 in	251.3274 in²

Using visual aids to learn this concept can help learners better understand how the change in radius and height can affect the surface area of a cylinder.

Practice Problems with Solutions

Let’s try a few practice problems to reinforce the concept of finding surface area of a cylinder.

Problem 1: Find the surface area of a cylinder with a radius of 6 cm and a height of 8 cm.

Solution:

Identify the radius and height of the cylinder.
- The radius of the cylinder is 6 cm.
- The height of the cylinder is 8 cm.
Plug these values into the formula.
Surface Area = 2π(6)² + 2π(6 x 8)
Simplify the expression using the order of operations.
Surface Area = 2π(36) + 2π(48)

Surface Area = 72π + 96π

Surface Area = 168π
Calculate the final numerical value of the surface area in square centimeters.
Surface Area ≈ 1056.64 cm²

Problem 2: Find the surface area of a conical drill bit with a base radius of 1 inch and a slant height of 3 inches.

Solution:

A conical drill bit is not a cylinder but a cone, so we cannot use the formula for finding surface area of a cylinder to calculate its surface area. Instead, we need to use the formula for finding surface area of a cone, which is:

Surface Area = πr² + πrL

Where:

r is the radius of the base of the cone
L is the slant height of the cone
π is a mathematical constant that approximates to 3.14

Now, let’s use this formula to find the surface area of the conical drill bit:

Identify the radius and slant height of the cone.
- The radius of the base is 1 inch.
- The slant height of the cone is 3 inches.
Plug these values into the formula.
Surface Area = π(1)² + π(1 x 3)
Simplify the expression using the order of operations.
Surface Area = π(1) + π(3)

Surface Area = π + 3π

Surface Area = 4π (in square inches)
Calculate the final numerical value of the surface area in square inches.
Surface Area ≈ 12.5664 in²

It’s crucial to be familiar with the formulas of different shapes to calculate their surface areas correctly.

Comparing Surface Areas of Different Cylinders

When comparing surface areas of cylinders, it’s essential to understand the relationship between surface area and volume. Suppose you have two cylinders with the same height but different radii. In that case, the cylinder with a larger radius will have a larger surface area than the other cylinder. However, the volume of the cylinder with a larger radius will also be more prominent, making it a more massive cylinder.

The relationship between surface area and volume is known as the surface to volume ratio. As the surface area of a cylinder increases, so does its volume. It’s important to consider both surface area and volume when comparing different cylinders in real-world applications.

Applications of Surface Area of a Cylinder

The ability to find surface area of a cylinder is crucial in many industries. Here are a few real-world examples:

Manufacturing: Surface area calculations are necessary for determining material requirements and constraints, including the heat transfer rate.
Construction: To determine the amount of paint or another coating needed to cover a cylindrical structure, the surface area of the structure needs to be calculated.
Dairy industry: The surface area calculation is essential to determine the amount of heat required to pasteurize milk in cylindrical tanks.

Conclusion

Knowing how to find the surface area of a cylinder is essential for anyone working in industries that involve cylindrical objects. In this article, we’ve provided a step-by-step guide on how to find surface area of a cylinder using the formula, real-world examples, visual aids, and practice problems. Understanding the relationship between surface area and volume is also crucial. We hope this article has been helpful in explaining the process of finding surface area of a cylinder.