Step by step
The question
Question: draw the net of a box 6 by 4 by 3, and find its surface area.
The surface area is the area of all the outside faces together.
A net shows every face flat.
1 Unfold it
We cut along some edges and fold it flat.
Matching faces have the same colour.
2 Area of each face
Top and bottom: 6 × 4 is 24.
Front and back: 6 × 3 is 18.
The two sides: 4 × 3 is 12.
Careful!
Count every face in the net.
A box has 6 faces, not 3.
3 Add them all
We add all 6 faces: 108.
4 Check
Let's check another way.
The faces come in pairs.
One of each: 24 plus 18 plus 12 is 54.
Times 2 is 108.
So the answer is right!
Let's look back.
First: unfold it.
Then: area of each face.
Then: add them all.
Last: check.