6.GR.1 Lesson 5-2-part2 Apply Day · Set B
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5.2 · Part II

Second Practice Form · Independent Application and Spiral Review

Area of a Triangle · Base

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■ ADVANCED CONCEPT ANCHOR: 5.2 · Part II
1Area of Triangles
2The Structural Procedure
  1. Identify the base and the perpendicular height to that base
  2. A triangle is exactly half of a rectangle with the same base and height
  3. Multiply base by height, then divide by 2
3Mathematical Word Bank
  • Area of a Triangle (Área de un triángulo) — The space inside a triangle. A triangle is half of a rectangle with the same base and height, so A = ½ × b × h.
  • Base (Base) — Any side of a triangle can be the base. Once you pick a base, the height must be measured perpendicular (at a 90° angle) to it.
  • Height (Altura) — The straight-up distance from the base to the top corner.
  • Area (Área) — How much space is inside a flat shape.
  • Perpendicular (Perpendicular) — Two lines that meet to make a square corner (90 degrees).
  • Composite figure (Figura compuesta) — A shape made by putting two or more simple shapes together.
4Watch out
  • A common mistake in Area of Triangles is forgetting the ½ — students multiply base × height like a rectangle and stop there, or they use the triangle's slanted side instead of the perpendicular height that's already given. Always check: did I take half, and did I use the straight-up height, not the slanted side?
SECTION 1 REAL-WORLD CONTEXTS & PROBLEM SOLVING [Applications]
  1. 1 MULTIPLE CHOICE

    (Lesson 5.3) 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
  2. 2 MULTIPLE CHOICE

    (Lesson 5.3) 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
  3. 3 MULTIPLE CHOICE

    What is the area of a triangle with base 10 cm and height 6 cm?

    1. A30 sq cm
    2. B60 sq cm
    3. C16 sq cm
    4. D30 cm
    Formula
    Put the numbers in
    Work it out
    Answer with its unit
  4. 4 MULTIPLE CHOICE

    A triangle has an area of 24 sq ft and a base of 8 ft. What is the height?

    1. A6 ft
    2. B3 ft
    3. C16 ft
    4. D12 ft
    Formula
    Put the numbers in
    Work it out
    Answer with its unit
  5. 5 MULTIPLE CHOICE

    Why do we divide by 2 when finding the area of a triangle?

    1. AA triangle is exactly half of a rectangle with the same base and height
    2. BTriangles have 2 equal sides
    3. CThe base is always twice the height
    4. DWe always divide area formulas by 2
    ✏️ Workspace & Solution Steps
SECTION 2 MATHEMATICAL WRITING & ERROR ANALYSIS [Reasoning & Critique]
  1. 6 OPEN RESPONSE

    A rectangle is 12 ft by 8 ft. A diagonal line cuts it into two triangles. What is the area of each triangle? Explain how the triangle area formula relates to the rectangle area formula.

    ✏️ Mathematical Justification & Response
📐 CER MATHEMATICAL PROOF MATRIX (CER 2.0) SMP.3 / Proof & Justification

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

C Claim
State your direct mathematical answer/claim with units.
E Evidence
Cite exact numbers, calculations, dimensions, or graph data.
R Reasoning
Explain the mathematical theorem, property, or definition connecting evidence to claim.
Student Mastery Self-Assessment:
1 · Need More Support
2 · Getting Closer
3 · Got It / Solid
4 · Master / Can Teach It