Finding: Surface Area of Triangular Prism 1

- Mr Kim

Surface Area of the following prisms will be explained in this

lesson

Starts from slide number 36

Example 1

9 m

16 m

11 m

12 m

9 m

16 m

11 m

12 m

This is a Triangular Prism

9 m

16 m

11 m

Triangular Prism has 5 faces

12 m

1

2

3

4

5

We must calculate the Total Area of all 5

Faces

9 m

16 m

11 m

12 m

9 m

16 m

11 m

12 m

Front Area is

9 m

16 m

11 m

12 m

Front Area is

21

Always times by a half

for Triangles

9 m

16 m

11 m

12 m

Front Area is

921

9 m

16 m

11 m

12 m

Front Area is

11921

9 m

16 m

11 m

12 m

Now, the Back Area is the same as the Front

so…

11921

9 m

16 m

11 m

12 m

211921

Now, the Back Area is the same as the Front

so times by 2

9 m

16 m12 m

11 m

Now we are going to find the Side Area

211921

9 m

16 m12 m

211921

11 m

Now we are going to find the Side Area

9 m

16 m12 m

211921

11 m

Make sure to add that on

The Side Area is a Rectangle so just multiply

the numbers

9 m

16 m12 m

211921

11 m

The Side Area is a Rectangle so just multiply

the numbers

9 m

16 m12 m

211921

11 m

16

The Side Area is a Rectangle so just multiply

the numbers

9 m

16 m12 m

211921

11 m

1216

9 m

16 m12 m

211921

11 m

But the other Side is the same as well so…

1216

9 m

16 m12 m

211921

11 m

But the other Side is the same as well so

times by 2

21216

9 m

16 m12 m

211921

11 m

Now we are going to find the Bottom Area

21216

9 m

16 m12 m

211921

11 m

21216

Now we are going to find the Bottom Area

9 m

16 m12 m

211921

11 m

21216

Make sure to add that on as well

9 m

16 m12 m

211921

11 m

The Bottom Area is a Rectangle as well so

just multiply the numbers

21216

9 m

16 m12 m

211921

11 m

21216

9

The Bottom Area is a Rectangle as well so

just multiply the numbers

9 m

16 m12 m

211921

11 m

21216

169

The Bottom Area is a Rectangle as well so

just multiply the numbers

9 m

16 m12 m

211921

11 m

Putting this altogether in the calculator

gives…

21216

169

9 m

16 m12 m

211921

11 m

Putting this altogether in the calculator

gives…

212162627169 m

Our Final Answer!

Example 2

7 cm

8 cm

12.5 cm

10.6 cm

7 cm

8 cm

12.5 cm

10.6 cm

Once again we need to calculate the Area of all

5 Faces

7 cm

8 cm

12.5 cm

10.6 cm

Front Area is

7 cm

8 cm

12.5 cm

10.6 cm

Front Area is

21

7 cm

8 cm

12.5 cm

10.6 cm

Front Area is

8721

7 cm

8 cm

12.5 cm

10.6 cm

And the Back Area is the same as the Front

so…

8721

7 cm

8 cm

12.5 cm

10.6 cm

28721

And the Back Area is the same as the Front

so times by 2

7 cm

8 cm

12.5 cm

10.6 cm

Now we are going to find the Right Side

Area

28721

7 cm

8 cm

12.5 cm

10.6 cm

Now we are going to find the Right Side

Area

28721

7 cm

8 cm

12.5 cm

10.6 cm

28721

Make sure to add that on

7 cm

8 cm

12.5 cm

10.6 cm

The Right Side is a Rectangle so just multiply

the numbers

28721

7 cm

8 cm

12.5 cm

10.6 cm

The Right Side is a Rectangle so just multiply

the numbers

28721

7 cm

8 cm

12.5 cm

10.6 cm

5.126.10

28721

The Right Side is a Rectangle so just multiply

the numbers

7 cm

8 cm

12.5 cm

10.6 cm

Now we are going to find the Left Side Area

5.126.10

28721

7 cm

8 cm

12.5 cm

10.6 cm

Now we are going to find the Left Side Area

28721

5.126.10

7 cm

8 cm

28721

5.126.1012.5 cm

10.6 cm

Make sure to add that on

7 cm

8 cm

12.5 cm

10.6 cm

The Left Side is a Rectangle as well

28721

5.126.10

7 cm

8 cm

12.5 cm

10.6 cm

So the Left Side Area is

28721

5.126.10

7 cm

8 cm

12.5 cm

10.6 cm

So the Left Side Area is

28721

5.126.10

7 cm

8 cm

12.5 cm

10.6 cm

7

28721

5.126.10

So the Left Side Area is

7 cm

8 cm

12.5 cm

10.6 cm

So the Left Side Area is

7

28721

5.126.10

7 cm

8 cm

12.5 cm

10.6 cm

7

28721

5.126.10

If it’s 12.5 cm there

7 cm

8 cm

12.5 cm

10.6 cm

7

It’s 12.5 cm there as well

28721

5.126.1012.5 cm

7 cm

8 cm

12.5 cm

10.6 cm

5.127

28721

5.126.10

It’s 12.5 cm there as well

12.5 cm

7 cm

8 cm

12.5 cm

10.6 cm

5.127

Now finally, we need to find the Bottom Area

12.5 cm

28721

5.126.10

7 cm

8 cm

12.5 cm

10.6 cm

5.127

Now finally, we need to find the Bottom Area

12.5 cm

28721

5.126.10

7 cm

8 cm

12.5 cm

10.6 cm

5.127

12.5 cm

28721

5.126.10

Make sure to add that on

7 cm

8 cm

12.5 cm

10.6 cm

The Bottom Area is a Rectangle as well so just

multiply the numbers

5.127

12.5 cm

28721

5.126.10

7 cm

8 cm

12.5 cm

10.6 cm

The Bottom Area is a Rectangle as well so just

multiply the numbers

5.127

12.5 cm

28721

5.126.10

7 cm

8 cm

12.5 cm

10.6 cm

5.1275.128

12.5 cm

28721

5.126.10

The Bottom Area is a Rectangle as well so just

multiply the numbers

7 cm

8 cm

10.6 cm

5.1275.128

12.5 cm

Putting this altogether in the calculator

gives…

12.5 cm

28721

5.126.10

7 cm

8 cm

10.6 cm

5.1275.128

12.5 cm

Putting this altogether in the calculator

gives…

2376cmOur Final Answer!

12.5 cm

28721

5.126.10