5.3 · Part II
Supported Application · Guided Entry to Today's Problem
Area of Trapezoids · Trapezoid
- A trapezoid is a four-sided shape with one pair of parallel bases
- Add the two bases together: (b1 + b2)
- Multiply by the perpendicular height, then take half
- 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.
- 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?"
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1 MULTIPLE CHOICE
A trapezoid has bases of 5 in and 9 in, and a height of 6 in. What is its area?
- A42 sq in
- B84 sq in
- C27 sq in
- D30 sq in
FormulaPut the numbers inWork it outAnswer with its unit- 1Name itWhich measure is asked?
- 2Write the formulaBefore any numbers.
- 3SubstituteMatch each letter.
- 4Unitunits, sq units, or cubic?
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2 MULTIPLE CHOICE
(Lesson 5.1) What is the area of a parallelogram with base 10 cm and height 7 cm?
- A70 sq cm
- B34 sq cm
- C17 sq cm
- D70 cm
FormulaPut the numbers inWork it outAnswer with its unit- 1Name itWhich measure is asked?
- 2Write the formulaBefore any numbers.
- 3SubstituteMatch each letter.
- 4Unitunits, sq units, or cubic?
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3 MULTIPLE CHOICE
(Lesson 5.1) A parallelogram has an area of 54 sq ft and a base of 9 ft. What is the height?
- A6 ft
- B45 ft
- C63 ft
- D27 ft
FormulaPut the numbers inWork it outAnswer with its unit- 1Name itWhich measure is asked?
- 2Write the formulaBefore any numbers.
- 3SubstituteMatch each letter.
- 4Unitunits, sq units, or cubic?
Writing Task: Justify why your mathematical solution is accurate and complete.
5.3 · Part II
On-Level Application · Standard Rigor
Area of Trapezoids · Trapezoid
- A trapezoid is a four-sided shape with one pair of parallel bases
- Add the two bases together: (b1 + b2)
- Multiply by the perpendicular height, then take half
- 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.
- 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?"
-
1 MULTIPLE CHOICE
Blueprint 1: A trapezoidal lobby window has bases of 6 ft and 10 ft and a height of 4 ft. What is its area for the glass order?
- A32 sq ft
- B40 sq ft
- C16 sq ft
- D60 sq ft
FormulaPut the numbers inWork it outAnswer with its unit -
2 MULTIPLE CHOICE
Blueprint 2: A trapezoidal skylight has bases of 9 ft and 7 ft and a height of 6 ft. What is its area?
- A48 sq ft
- B96 sq ft
- C63 sq ft
- D44 sq ft
FormulaPut the numbers inWork it outAnswer with its unit -
3 MULTIPLE CHOICE
Two equal trapezoid windows join to form a parallelogram with area 96 sq ft. What is the area of ONE trapezoid?
- A48 sq ft
- B96 sq ft
- C16 sq ft
- D192 sq ft
FormulaPut the numbers inWork it outAnswer with its unit
Writing Task: Justify why your mathematical solution is accurate and complete.
5.3 · Part II
Extension & Non-Routine Application
Area of Trapezoids · Trapezoid
- A trapezoid is a four-sided shape with one pair of parallel bases
- Add the two bases together: (b1 + b2)
- Multiply by the perpendicular height, then take half
- 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.
- 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?"
-
1 MULTIPLE CHOICE
A trapezoidal window has parallel edges of 4 feet and 8 feet and a height of 5 feet. What is its area?
- A30 square feet
- B60 square feet
- C20 square feet
- D17 square feet
FormulaPut the numbers inWork it outAnswer with its unit
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2 OPEN RESPONSE
Design a trapezoid whose area is exactly 24 sq ft, where one base is 4 ft LONGER than the other. Give both bases and the height, and show your design checks out. Could a classmate's correct design use different numbers than yours?
✏️ Mathematical Justification & Response
Writing Task: Justify why your mathematical solution is accurate and complete.