Trapezoids

Trapezoids

What are they?

How can we calculate their areas?

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

• Altitudes

• Widths

• Lengths

Multiple Choice

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

• Length

• Height

• Base

• Width

So that's where the 1/2 and the (b₁ + b₂) come from!

Let's see an example of how this works...

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 Select

Our answer was missing units! What should the area units be? (There are TWO correct answers!)

• ft

• ft²

• units

• sq ft

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