Area of Trapezoids Guided Practice

Vocabulary

Trapezoid's have 2 PARALLEL bases.

Base 1: Top Length

Base 2: Bottom Length

Height MUST be perpendicular from the base [90 degrees].

Let's try it!

The bases of this trapezoid are 6 units and 10 units. The height of this trapezoid is 7 units.

A = 1/2 (6 + 10)(7)

A = 1/2 (16)(7)

A = (8)(7)

A =56

So, the area of the trapezoid is 56 square units.

Multiple Select

What properties do ALL trapezoids have?

• 1 pair of Parallel Sides

• Right Angles

• 4 Sides

• Opposite Congruent Sides

Multiple Choice

What name do we use to label the 2 sides that are parallel?

• Bases

• Heights

• Widths

• Lengths

Multiple Choice

What name do we use to label the distance between the two bases?

• Length

• Height

• Base

• Width

Multiple Choice

What are the bases of the green trapezoid?

• 5 ft & 6 ft

• 6 ft & 9 ft

• 5 ft & 9 ft

Multiple Choice

What is the height of the green trapezoid?

• 5ft

• 6ft

• 9ft

Multiple Choice

Fill in the area formula for the green trapezoid.

$$A=\frac{1}{2}\cdot h\cdot\left(b_1+b_2\right)$$  

• $$A=\frac{1}{2}\cdot6\cdot\left(5+9\right)$$  

• $$A=\frac{1}{2}\cdot5\cdot\left(6+9\right)$$  

• $$A=\frac{1}{2}\cdot9\cdot\left(5+6\right)$$  

Multiple Choice

Shown is the correct formula for the green trapezoid. Which shows the next correct step?
$$A=\frac{1}{2}\cdot6\cdot\left(5+9\right)$$  

• $$A=\frac{1}{2}\cdot6\cdot14$$  

• $$A=\frac{1}{2}\cdot30+9$$  

• $$A=\frac{1}{2}\cdot6\cdot45$$  

Multiple Choice

Shown is the correct next step in calculating the area. So what should the area be?

$$A=\frac{1}{2}\cdot6\cdot14$$  

• 42

• 10

• 84

• 17

Multiple Choice

What are the bases of the red trapezoid?

• 8mm & 5mm

• 5mm & 4mm

• 8mm & 4mm

Multiple Choice

What is the height of the red trapezoid?

• 4mm

• 5mm

• 8mm

Multiple Choice

Fill in the area formula for the red trapezoid.

$$A=\frac{1}{2}\cdot h\cdot\left(b_1+b_2\right)$$  

• $$A=\frac{1}{2}\cdot5\cdot\left(4+8\right)$$

• $$A=\frac{1}{2}\cdot4\cdot\left(5+8\right)$$

• $$A=\frac{1}{2}\cdot8\cdot\left(4+5\right)$$

Multiple Choice

Shown is the correct formula. What's next?

$$A=\frac{1}{2}\cdot5\cdot\left(4+8\right)$$  

• $$A=\frac{1}{2}\cdot5\cdot12$$  

• $$A=\frac{1}{2}\cdot20\cdot40$$  

• $$A=\frac{1}{2}\cdot5\cdot32$$  

Multiple Choice

Shown is the correct next step. What is the area of the red trapezoid?

$$A=\frac{1}{2}\cdot5\cdot12$$  

• 30 sq mm

• 11 sq mm

• 70 sq mm

• 140 sq mm

Multiple Choice

What formula do we use to find the area of this shape?

• $$A\ =\frac{1}{2}bh$$
  

• $$A\ =\ \frac{1}{2}\left(b_1\ +b_2\right)h$$

Multiple Select

What two sides are the bases? (Identify both of them)

• 7

• 4

• 6

• 8

• 5

Multiple Select

What is the height of this trapezoid?

• 7

• 4

• 6

• 8

• 5

Hotspot

What two measurements will you not use to find the area of the trapezoid?

Multiple Select

Which formula can be used to find the area of the trapezoid?

• a = ½ (7+5) 4

• a = ½ (6+8) 4

• a = ½ (6 X 8) 4

• a = ½ (6+8)

Multiple Choice

A lampshade has a shape of a trapezoid. One base of the lampshade is 6 cm, the second base of the lampshade is 10. The height of the lampshade is x.

Which equation can be used to find A, the area of the face of the lampshade in square inches?

• $$A=\frac{1}{2}\left(6+10\right)y$$

• $$A=\frac{1}{2}\left(6+10\right)x$$

• $$A=\frac{1}{2}\left(6\right)+\left(10\right)x$$

• $$A=\frac{1}{2}\left(6\right)+\left(10\right)y$$

Multiple Choice

The bases of a trapezoid are 8 centimeters and 12 centimeters, and the height is h centimeters. Which equation can be used to represent A, the area of the trapezoid in square centimeters?

• $$A=\frac{1}{2}\left(8+12\right)h$$

• $$A=\frac{1}{2}\left(8\cdot12\right)h$$

• $$A=\left(8+12\right)h$$

• $$A=\left(8\cdot12\right)h$$

Fill in the Blanks

Multiple Choice

Which answer choice shows the area of this trapezoid correctly calculat

• A = ½ (15) (6)

  A = ½ (90)

  A = 45 ft²

• A= ½ (15 + 11) 6

  A = ½ (26) 6

  A= ½ (126)

  A = 78 ft²

• A = ½ (7 + 7) 6

  A = ½ (14) 6

  A = ½ (84)

  A = 42 ft²

• A = ½ (15 + 6) 7

  A = ½ (21) 7

  A = ½ (147)

  A = 73.5 ft²

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