Area of Trapezoid

Find the area of the figure. : 

Find the area of the figure. 6m 85m 8m 15m A I C D E F G B

Problem Opener : 

Problem Opener Raven’s lot is trapezoid in shape. She wants to plant Bermuda grass all over the area. She knew that Bermuda is bought per square meter. How will Raven know the number of square meters of Bermuda grass she has to buy?

Development of the formula for the area of a trapezoidal region : 

Development of the formula for the area of a trapezoidal region R b1 b2 W B A Identify the base & height of sABW. Ans. sABW has a base b2 and height h. Identify the base & height of sAWR. Ans. sAWR has a base b1 and height h. h h Area of the Trapezoid is Area of sABW + Area of sAWR Area of Trapezoid = 1/2bh + 1/2bh or A=1/2 h(b1+b2)

Slide 4: 

Area of a Trapezoid height Base 1 Formula: A = ½ h(b1+b2) Base 2

Slide 5: 

Area of a Trapezoid Base 2=4cm height=5cm Base 1=7cm Formula: A = ½ h(b1+b2)

Slide 6: 

Area of a Trapezoid Base 2=4cm height=5cm Base 1=7cm A=5cm x (4cm+7cm)/2 A=5cm x (11cm) /2 A= 55cm²/2 A=27.5 cm² Formula: A = ½ h(b1+b2)

Slide 7: 

Area of a Trapezoid Base 2=4cm height=5cm Base 1=7cm A=5cm x (4cm+7cm)/2 A=5cm x (11cm) /2 A= 55cm²/2 A=27.5 cm² Formula: A = ½ h(b1+b2)

Slide 8: 

Area of a Trapezoid Base 2 = 5cm height=6cm Base 1 = 9cm A= 6cm x (9cm+5cm) / 2 A= 6cm x 14cm / 2 A= 84cm² / 2 A= 42 cm² Formula: A = ½ h(b1+b2)

Slide 9: 

Let’s see it one more time. Base 2 = 5cm height=6cm Base 1 = 9cm A= 6cm x (9cm+5cm) / 2 A= 6cm x 14cm / 2 A= 84cm² / 2 A= 42 cm² Formula: A = ½ h(b1+b2)

Slide 10: 

Area of a Trapezoid Base 2 = 6cm Base 1 = 10cm A= 5cm x (10cm+6cm) / 2 A= 5cm x 16cm / 2 A= 80cm² / 2 A= 40 cm² Formula: A = ½ h(b1+b2) height=5cm

Slide 11: 

Area of a Trapezoid Base 2=6cm height=12cm Base 1=10cm A=12cm x (10cm+6cm)/2 A=12cm x (16cm) /2 A= 192cm²/2 A=96 cm² Formula: A = ½ h(b1+b2)