Determine the Area of Trapezoids
Name Period
Objectives / Objetivos
Content Objective: I can find the area of a trapezoid using the formula A = ½(b1 + b2) × h.
Language Objective: I can explain my steps using the words trapezoid, base, height, and area.
Key Idea / Idea clave
Area of Trapezoids. Formula: Area = ½ × (b1 + b2) × h. 1. A trapezoid is a four-sided shape with one pair of parallel bases. 2. Add the two bases together: (b1 + b2). 3. Multiply by the perpendicular height, then take half
I Notice / Observo
- What shape is the window?
- How many parallel sides does it have?
I Wonder / Me pregunto
- Why does the formula use two bases instead of one?
Vocabulary / Vocabulario
| Term / Término | Definition / Definición |
|---|---|
| Area of Trapezoids Área de trapecios | The space inside a trapezoid. Formula: A = 1/2(b₁ + b₂)h. El espacio dentro de un trapecio. Fórmula: A = 1/2(b₁ + b₂)h. |
| Trapezoid Trapecio | A four-sided shape with just one pair of parallel sides. Una figura de cuatro lados con solo un par de lados paralelos. |
| Parallel Paralelas | Two lines or sides that stay the same distance apart and never meet. Dos líneas o lados que se mantienen a la misma distancia y nunca se cruzan. |
| Base 1 (b1) Base 1 (b1) | One of the two parallel sides of a trapezoid. Uno de los dos lados paralelos de un trapecio. |
| Base 2 (b2) Base 2 (b2) | The other parallel side of a trapezoid. El otro lado paralelo de un trapecio. |
| Height Altura | The straight-up distance between the two parallel sides. La distancia recta entre los dos lados paralelos. |
Practice Preview / Vista previa de práctica
Read each task. Show your work in the spaces provided and explain how you know.
1. What is the area of a trapezoid with bases 6 cm and 10 cm, and height 4 cm?
- A 24 sq cm
- B 32 sq cm
- C 40 sq cm
- D 64 sq cm
Answer:
2.
Complete each empty cell. Show your reasoning below.
| Trapezoid | Base 1 | Base 2 | Height | Area |
|---|---|---|---|---|
| Window A | 8 ft | 4 ft | 5 ft | |
| Window B | 12 ft | 6 ft | 4 ft | |
| Window C | 10 ft | 8 ft | 72 sq ft | |
| Window D | 5 ft | 6 ft | 48 sq ft |
3. Match each shape to its area.
Write the letter of the matching item in the blank.
| 1. | Trapezoid b₁=10, b₂=6, h=4 | A. | 32 sq units | |
| 2. | Trapezoid b₁=8, b₂=4, h=5 | B. | 45 sq units | |
| 3. | Trapezoid b₁=12, b₂=8, h=4 | C. | 21 sq units | |
| 4. | Triangle b=14, h=6 | D. | 42 sq units | |
| 5. | Parallelogram b=9, h=5 | E. | 40 sq units | |
| 6. | Rectangle 7×3 | F. | 30 sq units |
4. Find the Area Error
Which step has the mistake, and what should it be?
Reflection / Reflexión
One thing I learned today / Una cosa que aprendí hoy: