6.GR.1 Lesson 5-3-group1 🟡 Group 1 · Support & Scaffolding
MASTERY CHECK
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5.3 Small Group · Group 1

Tier 2 Intervention · Concrete-Representational-Abstract (CRA) · Dual-Language Anchors

Area of Trapezoids · Trapezoid · Procedural Fluency · Real-World Applications

Interactive Workbench & Models →
Name: Date: Period: Learning Goal:
■ CONCEPT SUMMARY & GUIDED NOTES: Let's build it together — How do we find the area of a trapezoid?
1Area of a trapezoid = ½ × (base 1 + base 2) × height. We add the two bases first, then take half.
  • A trapezoid is a four-sided shape with one pair of parallel sides. The two parallel sides are called the bases, and they have different lengths. We'll walk through a worked example, try one together, then you'll try a few with hints right there when you need them.
2Worked Example — Watch me
  1. My trapezoid window has a top base of 4 feet, a bottom base of 8 feet, and a height of 5 feet.
  2. I write the formula: A = ½ × (b1 + b2) × h.
  3. I add the bases first: 4 + 8 = 12.
  4. I multiply by the height: 12 × 5 = 60.
  5. I take half: ½ × 60 = 30. So the area is 30 square feet.
3Mathematical Word Bank
  • Area of Trapezoids (Área de trapecios) — The space inside a trapezoid. Formula: A = 1/2(b₁ + b₂)h.
  • Trapezoid (Trapecio) — A four-sided shape with just one pair of parallel sides.
  • Parallel (Paralelas) — Two lines or sides that stay the same distance apart and never meet.
  • Base 1 (b1) (Base 1 (b1)) — One of the two parallel sides of a trapezoid.
  • Base 2 (b2) (Base 2 (b2)) — The other parallel side of a trapezoid.
  • Height (Altura) — The straight-up distance between the two parallel sides.
4Watch out
  • A common mistake in Area of Trapezoids is forgetting the ½ in A = ½ × (b1 + b2) × h. After adding the bases and multiplying by the height, students stop there instead of taking half — for example, with bases 6 ft and 10 ft and a height of 4 ft, they compute (6 + 10) × 4 = 64 sq ft instead of taking half to get the correct 32 sq ft. That unhalved number is really the area of the parallelogram made from two trapezoids, not the area of one trapezoid. Before you submit, always ask: "Did I take half of my last answer?"
SECTION 1 CONCEPTUAL UNDERSTANDING & VISUAL MODELS [Visual Modeling]
  1. 1 FILL TABLE

    Use the formula A = ½ × (b₁ + b₂) × h to find the area of each trapezoid.

    TrapezoidBase 1Base 2HeightArea
    Shape A
    Shape B
    ✏️ Scratchpad / Reasoning
  2. 2 FILL TABLE

    Solve the mathematical problem. Show all of your work and reasoning.

    TrapezoidBase 1Base 2HeightArea
    Window A
    Window B
    Window C
    Window D
    ✏️ Scratchpad / Reasoning
SECTION 2 REAL-WORLD CONTEXTS & PROBLEM SOLVING [Applications]
  1. 3 MULTIPLE CHOICE

    What is the area of a trapezoid with bases 6 cm and 10 cm, and height 4 cm?

    1. A32 sq cm
    2. B64 sq cm
    3. C24 sq cm
    4. D40 sq cm
    Formula
    Put the numbers in
    Work it out
    Answer with its unit
    1. 1Name itWhich measure is asked?
    2. 2Write the formulaBefore any numbers.
    3. 3SubstituteMatch each letter.
    4. 4Unitunits, sq units, or cubic?
  2. 4 MULTIPLE CHOICE

    A trapezoid has an area of 45 sq ft, bases of 7 ft and 11 ft. What is the height?

    1. A5 ft
    2. B9 ft
    3. C3 ft
    4. D10 ft
    Formula
    Put the numbers in
    Work it out
    Answer with its unit
    1. 1Name itWhich measure is asked?
    2. 2Write the formulaBefore any numbers.
    3. 3SubstituteMatch each letter.
    4. 4Unitunits, sq units, or cubic?
  3. 5 MULTIPLE CHOICE

    What is the first step when finding the area of a trapezoid?

    1. AAdd the two bases together
    2. BMultiply the two bases
    3. CSubtract the shorter base from the longer base
    4. DDivide the height by 2
    ✏️ Workspace & Solution Steps
  4. 6 MULTIPLE CHOICE

    A trapezoid has bases of 5 in and 9 in, and a height of 6 in. What is its area?

    1. A42 sq in
    2. B84 sq in
    3. C27 sq in
    4. D30 sq in
    Formula
    Put the numbers in
    Work it out
    Answer with its unit
    1. 1Name itWhich measure is asked?
    2. 2Write the formulaBefore any numbers.
    3. 3SubstituteMatch each letter.
    4. 4Unitunits, sq units, or cubic?
🗣️ MATHEMATICAL DISCOURSE & TALK MOVES SMP.3 / Construct Viable Arguments

Group Discussion Prompt: How does your visual model justify your mathematical solution?

🗣️ Partner A:
Partner A: "I modeled this by identifying the relationship and..."
👂 Partner B:
Partner B: "I agree with your step because the standard mathematical rule states..."
✍️ The Writing Revolution (TWR) · Sentence Expansion Because · But · So

Complete each sentence stem to demonstrate precise mathematical reasoning:

BECAUSE The mathematical model proves the solution because each step preserves quantitative equivalence.
BUT An estimate provides a quick benchmark, but an exact proof is required for precision.
SO The quantities follow the standard rule, so the final result is verified with certainty.
📐 CER MATHEMATICAL PROOF MATRIX (CER 2.0) SMP.3 / Proof & Justification

Writing Task: Justify why your mathematical solution is accurate and complete.

C Claim
Starter: My mathematical claim is that the solution is...
E Evidence
Starter: The evidence from the model/table demonstrates that...
R Reasoning
Starter: This proves my answer because the standard mathematical definition of...
Student Mastery Self-Assessment:
1 · Need More Support
2 · Getting Closer
3 · Got It / Solid
4 · Master / Can Teach It