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

Second Practice Form · Independent Application and Spiral Review

Area of Parallelograms · Slanted side

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■ ADVANCED CONCEPT ANCHOR: 5.1 · Part II
1Area of Parallelograms & Rhombuses
2The Structural Procedure
  1. Identify the base (any side)
  2. Identify the perpendicular height (height must be perpendicular to base, not slanted)
  3. Multiply base times height; label with square units (e.g. cm², in²)
3Mathematical Word Bank
  • Area of Parallelograms (Área de paralelogramos) — The space inside a parallelogram. Formula: A = b × h, using the perpendicular height.
  • Slanted side (Lado inclinado) — A side that leans instead of going straight up and down. It is not the perpendicular height.
  • Parallelogram (Paralelogramo) — A four-sided shape with two pairs of parallel sides.
  • Parallel (Paralelas) — Two lines or sides that stay the same distance apart and never meet.
  • Base (Base) — Any side of a parallelogram 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.
4Watch out
  • The most common mistake in Area of Parallelograms is multiplying the base by the slanted side instead of the perpendicular height. For a parallelogram with a base of 16 ft, a perpendicular height of 9 ft, and a slanted side of 11 ft, students compute 16 × 11 = 176 square feet instead of the correct 16 × 9 = 144 square feet. The height must be the straight-up (perpendicular) distance between the base and its opposite side, not the length of the slanted side, even though the slanted side is often the number that 'looks' like it belongs in the formula.
  1. 1 MULTIPLE CHOICE

    A parallelogram-shaped patio has a base of 16 feet and a perpendicular height of 9 feet. What is its area?

    1. A144 square feet
    2. B50 square feet
    3. C72 square feet
    4. D25 square feet
    Formula
    Put the numbers in
    Work it out
    Answer with its unit
  2. 2 MULTIPLE CHOICE

    What is the area of a parallelogram with base 10 cm and height 7 cm?

    1. A70 sq cm
    2. B34 sq cm
    3. C17 sq cm
    4. D70 cm
    Formula
    Put the numbers in
    Work it out
    Answer with its unit
  3. 3 MULTIPLE CHOICE

    A parallelogram has an area of 54 sq ft and a base of 9 ft. What is the height?

    1. A6 ft
    2. B45 ft
    3. C63 ft
    4. D27 ft
    Formula
    Put the numbers in
    Work it out
    Answer with its unit
  4. 4 MULTIPLE CHOICE

    What is the area of a parallelogram with base 9 cm and height 5 cm?

    1. A45 sq cm
    2. B14 sq cm
    3. C22.5 sq cm
    4. D90 sq cm
    Formula
    Put the numbers in
    Work it out
    Answer with its unit
📐 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