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6th grade · Math · Unit 17 of 21

Nets & Surface Area

Unfold a box

What your child practices

Using nets made of rectangles and triangles to find the surface area of prisms and pyramids.

New York State Learning Standards learning standard: NY-6.G.4 · showing three-dimensional figures with nets and using them to find surface area

How we explain it

Children can open this short lesson before they practice.

  1. A net is a solid unfolded flat.
  2. Find the area of every face in the net.
  3. Add them all: that is the surface area.

Example: A box is 2 cm by 3 cm by 4 cm. What is its surface area? Two 2 × 3 faces: 12. Two 2 × 4 faces: 16. Two 3 × 4 faces: 24. 12 + 16 + 24 = 52. Answer: 52 cm²

Nets & Surface Area in New York

In the New York State Learning Standards, this is unit 17 of 21 in 6th grade Math, after Unit Rates and before Samples & Populations.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: New York State Education Department (NYSED)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    A cube has edges 5 in long. What is its surface area?

    • 150 in²
    • 30 in²
    • 100 in²
    • 125 in²
    • 147 in²

  2. Question 2

    A box is 4 cm by 7 cm by 4 cm. Use its net to find its surface area.

    • 142 cm²
    • 112 cm²
    • 100 cm²
    • 144 cm²
    • 72 cm²

  3. Question 3

    Which shapes make up a net of a triangular pyramid?

    • 6 triangles
    • 4 triangles
    • 2 triangles and 3 rectangles
    • 3 triangles and 1 square

  4. Question 4

    A square pyramid has a base 5 ft on each side. Each triangle face has a height of 9 ft. What is its surface area?

    • 90 ft²
    • 205 ft²
    • 140 ft²
    • 114 ft²
    • 115 ft²

  5. Question 5

    A box is 8 cm by 3 cm by 5 cm. Use its net to find its surface area.

    • 156 cm²
    • 103 cm²
    • 158 cm²
    • 79 cm²
    • 120 cm²

  6. Question 6

    A cube has edges 8 in long. What is its surface area?

    • 512 in²
    • 385 in²
    • 256 in²
    • 384 in²
    • 48 in²

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