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### Course: 6th grade (Illustrative Mathematics)>Unit 1

Lesson 9: Lesson 14: Nets and surface area

# Surface area using a net: triangular prism

Here are the steps to compute the surface area of a triangular prism: 1. Find the areas of each of the three rectangular faces, using the formula for the area of a rectangle: length x width. 2. Next, find the area of the two triangular faces, using the formula for the area of a triangle: 1/2 base x height. 3. Add the areas of all five faces together, and you're done!

## Want to join the conversation?

• At How did he get 1/2
• Like i said to selion if your talking about how he got the 1/2, thats apart of the formula. Which is, Half of the base times the height, OR, Half the height times the base
• i need help on nets and surface area
• If you don't understand this, try going back to Unit 8 - Plane figures (if you haven't already done it, complete it before going back to this). You can also try the course called "Getting ready for 6th grade."

Here is how to find areas of different parts of nets:

The formula for a triangle is 1/2 times Base times Height.

The formula for a square is Base times Height.

The formula for a parallelogram is to break it into two smaller triangles, switch it around to make a square, and find Base times Height of the square.

The formula for any other shape is break into other shapes (triangles, squares, etc.), find the area for all the broken-up shapes, and add it all up.

Once you have found the area for all the parts of the net, add the parts together to find the area of a net.
Hope this helps!
• How many nets for a prism is there?
• There are 9 nets
• sooo i ahve a question to anyone who whould like too answer me....... HOW DO YOU DO THIS? im so lost its sad can yall please help!
• A= HB/2 (Half of the base times height, Thats the formula for a triangle, i dont have time to give you the other formulas but i hoped this helped.
• Do you always have to multiply by 1/2?
• If you're trying to find the surface area of the triangles, then yes. You always have to multiply by 1/2 to find the area of the triangles.
• is there a better way to explain this like a talk through b/c is still dont understand.