Student Help Card

Lesson 6: Represent Three-Dimensional Figures in Two Dimensions6.GR.4

Stuck? Start here. Read the steps, try the problem, then check your answer.

I can…

I can find the surface area of a solid by using its net.

Surface Area Using Nets — The total area of all the faces of a solid. A net unfolds the solid flat so you can see every face and add their areas.
Surface area — The total area of all the flat sides of a solid.
Net — A flat shape that folds up into a solid.
Face — One flat side of a solid shape.
Two-dimensional — A flat shape with length and width, but no thickness.
Edge — The line where two flat sides of a solid meet.
Pyramid — A solid with one base and triangular sides that meet at a point.
Vertex — A corner point where edges meet.

My box is 8 in. long, 5 in. wide, and 3 in. tall. I unfold it into a net and see 3 pairs of faces.
Top and bottom: each is 8 × 5 = 40, and there are 2 of them, so 2 × 40 = 80.
Front and back: each is 8 × 3 = 24, so 2 × 24 = 48.
Left and right: each is 5 × 3 = 15, so 2 × 15 = 30.
I add all the pairs: 80 + 48 + 30 = 158. The surface area is 158 in².

You wrap a shoebox as a birthday gift. The box has l = 10 in, w = 5 in, h = 2 in. How much wrapping paper covers it exactly (its surface area)?

160 in²

SA = 2(10×5) + 2(10×2) + 2(5×2) = 100 + 40 + 20 = 160 in². Surface area uses square units (in²).

I know ___ because ___.

Goal: I can explain my work using the words surface area, net, face, and two-dimensional.