How do you find the surface area of a cylinder??

Actually if the radius is r, the surface area is 4*pi*r^2

Would it be possible to find the surface area of a sphere?

if the radius is r, the surface area is 4*pi*r^2

the question to find the surface area of a square with sides 2 1/2 confuses me. can someone please explain in detail how to solve this problem?

Basically, 2 1/2 equals 2.5. So the easiest way to do that is obviously by multiplying 2.5*2.5*6 By the way, * equals multiply.

What if we don't have a decimal and just a normal number?

That's ok, you won't always get a decimal or fraction. Hope this helps, have a great day.

How do you find the surface area of a cylinder

The total surface area of the cylinder formula is the sum of the base surface area and the lateral surface area: total_area = base_area + lateral_area , or total_area = 2 * π * r² + (2 * π * r) * h , or total_area = 2 * π * r * (r + h) .

How do you find the height of a cuboid, when the length, the width and the surface area is given?

Surface area of cuboid = 2(lb+bh+hl) So you put the values and then solve.

how to find the area of a square pyramid?

I assume you mean the surface area, since a square pyramid is 3-dimensional. For a right square pyramid with base side length s and slant height L, the total surface area is the area of the square base with side length s, plus the total area of four triangles each with base s and altitude L. So the total surface area is s^2 + 4(1/2)(sL) = s^2 + 2sL. (Note well: the slant height is *not* the same as the vertical height.)

Main content

Basic geometry and measurement

Course: Basic geometry and measurement > Unit 9

Lesson 3: Finding surface area

Surface area review

Google Classroom

Review surface area and try some practice problems.

What is surface area?

Surface area is the amount of space covering the outside of a three-dimensional shape.

Finding surface area

To calculate surface area, we add the areas of all the faces of the three-dimensional figure.

Want to learn more about finding surface area? Check out this video.

Example: Rectangular prism

Find the surface area of the right rectangular prism shown below.

Let's draw a net of the rectangular prism.

[What is a net?]

Each of the sides is a 4 by 1, point, 5 rectangle.

\begin{aligned} \text{Area of a rectangle} &= \text{length} \cdot \text{width}\\\\ &= 4 \cdot 1.5\\\\ &= {6} \\\\ \end{aligned}

The total area of both sides is 2, dot, 6, equals, start color #11accd, 12, end color #11accd.

The bottom and the top are both 4 by 5 rectangles.

\begin{aligned} \text{Area of a rectangle} &= \text{length} \cdot \text{width}\\\\ &= 4 \cdot 5\\\\ &= {20} \\\\ \end{aligned}

The total area of bottom and the top is 2, dot, 20, equals, start color #1fab54, 40, end color #1fab54.

The back and the front are both 1, point, 5 by 5 rectangles.

\begin{aligned} \text{Area of a rectangle} &= \text{length} \cdot \text{width}\\\\ &= 1.5 \cdot 5\\\\ &= {7.5} \\\\ \end{aligned}

The total area of the back and the front is 2, dot, 7, point, 5, equals, start color #e07d10, 15, end color #e07d10.

Let's add the areas to find the surface area.

\begin{aligned} \text{Surface area} &= \blueD{12}+ \greenD{40} + \goldD{15} \\\\ &= 67\\\\ \end{aligned}

The surface area of the rectangular prism is 67 unitssquared.

Practice set

Problem 1

Current

Find the surface area of the square pyramid shown below.

unitssquared

Want to try some more surface area problems? Check out this exercise.

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Bee
Posted 6 years ago. Direct link to Bee's post “How do you find the surfa...”
How do you find the surface area of a cylinder??
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- TTV.StreamSniper.YT
  Posted 5 years ago. Direct link to TTV.StreamSniper.YT's post “Actually if the radius is...”
  Actually if the radius is r, the surface area is 4*pi*r^2
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David966★_
Posted 6 years ago. Direct link to David966★_'s post “Would it be possible to f...”
Would it be possible to find the surface area of a sphere?
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- Timber Lin
  Posted 6 years ago. Direct link to Timber Lin's post “if the radius is r, the s...”
  if the radius is r, the surface area is 4*pi*r^2
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Aeonos Shroud
Posted 6 years ago. Direct link to Aeonos Shroud's post “the question to find the ...”
the question to find the surface area of a square with sides 2 1/2 confuses me. can someone please explain in detail how to solve this problem?
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- gopal2373
  Posted 5 years ago. Direct link to gopal2373's post “Basically, 2 1/2 equals 2...”
  Basically, 2 1/2 equals 2.5. So the easiest way to do that is obviously by multiplying 2.5*2.5*6 By the way, * equals multiply.
  Comment on gopal2373's post “Basically, 2 1/2 equals 2...”
  (19 votes)
Conner Steinborn
Posted 4 years ago. Direct link to Conner Steinborn's post “What if we don't have a d...”
What if we don't have a decimal and just a normal number?
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- P7 Logan, Aaron
  Posted 4 years ago. Direct link to P7 Logan, Aaron's post “That's ok, you won't alwa...”
  That's ok, you won't always get a decimal or fraction.
  
  Hope this helps, have a great day.
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Nicholes Adams
Posted 3 years ago. Direct link to Nicholes Adams's post “How do you find the surfa...”
How do you find the surface area of a cylinder
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- ®¥ħ@
  Posted 10 months ago. Direct link to ®¥ħ@'s post “The total surface area of...”
  The total surface area of the cylinder formula is the sum of the base surface area and the lateral surface area: total_area = base_area + lateral_area , or total_area = 2 * π * r² + (2 * π * r) * h , or total_area = 2 * π * r * (r + h) .
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How about to find the surface area of a hyperboloid?
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Vineetha V Banavar
Posted 5 years ago. Direct link to Vineetha V Banavar's post “How do you find the heigh...”
How do you find the height of a cuboid, when the length, the width and the surface area is given?
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- neelshaan2004
  Posted 4 years ago. Direct link to neelshaan2004's post “Surface area of cuboid = ...”
  Surface area of cuboid = 2(lb+bh+hl)
  So you put the values and then solve.
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Emily.Mitchell
Posted 4 years ago. Direct link to Emily.Mitchell's post “how to find the area of a...”
how to find the area of a square pyramid?
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- Ian Pulizzotto
  Posted 4 years ago. Direct link to Ian Pulizzotto's post “I assume you mean the sur...”
  I assume you mean the surface area, since a square pyramid is 3-dimensional.
  
  For a right square pyramid with base side length s and slant height L, the total surface area is the area of the square base with side length s, plus the total area of four triangles each with base s and altitude L. So the total surface area is
  s^2 + 4(1/2)(sL) = s^2 + 2sL.
  
  (Note well: the slant height is not the same as the vertical height.)
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Jack Vazquez
Posted 3 years ago. Direct link to Jack Vazquez's post “I Get it but I still need...”
I Get it but I still need help and a little bit of practice
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aidenburgos
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Why are questions called quetions... The more you know.........The less you are
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- Viccy
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  why is this so funny to me? anybody else??
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