Geometry Lessons Trapezoids Lesson 1 Launch Quadrilateral

Geometry Lessons Trapezoids Lesson 1

Launch Quadrilateral … PARALLELOGRAM 4 -sided shape What kind of quadrilateral is shown here? h = 8 b = 12 How would you find the AREA of this 4 -sided shape? Area = base x height Agenda 2

Launch Quadrilateral … TRAPEZOID 4 -sided shape What kind of quadrilateral is shown here? How would you find the AREA of this 4 -sided shape? Can I use Area = base x height? ? ? Agenda 3

Mini-Lesson The formula for the Area of a Trapezoid is… A = (b 1 + b 2) x h 2 b 2 height or h b 1 4 Agenda

A = (b 1 + b 2) x h 2 Let’s Test it out using the A = (8 + 4) x 2 2 Trapezoids from the Explore… A = (12) x 2 It works! 2 A= 6 x 2 = 12 sq. units b 2 = 4 Trapezoid A h = 2 5 b 1 = 8 Agenda

A = (b 1 + b 2) x h 2 A = (10 + 6) x 3 2 A = (16) x 3 2 Let’s try the formula again… Trapezoid B b 2 = 6 A= 8 x 3 A = 24 sq. units h = 3 6 It works! b 1 = 10 Agenda

So, this part of the formula means…. we take the AVERAGE of the base lengths, then multiply by the height to get the Area of a Trapezoid! 7 Agenda

Practice #1 b 2 = 5 h = 4 b 1 = 9 8 A = (b 1 + b 2) x h 2 A = (9 + 5) x 4 2 A = (14) x 4 2 A = 7 x 4 = 28 sq. units Agenda

Practice #2 b 2 = 3 h = 10 Now you try one… A = (b 1 + b 2) x h 2 A = (9 + 3) x 10 2 A = (12) x 10 2 A = 6 x 10 = 60 sq. units b 1 = 9 9 Agenda

Practice #3 Let’s try another one together, but make it a little more interesting! Edward wants make a curtain for his living room window so he can sit in the dark and think of ways to get rid of Jacob! Calculate the area so that she knows how much fabric to buy. h = 7 ft b 2 = 4 ft 10 b 1 = 2 ft A = (b 1 + b 2) x h 2 A = (2 + 4) x 7 2 A = (6) x 7 2 A = 3 x 7 = 21 ft 2 Agenda

Practice #4 Now you try another one… Brian is getting a custom sticker to completely cover the back of his guitar. How much space will it take up? = 12 in b 2 h= 40 in 11 18 in b 1 = A = (b 1 + b 2) x h 2 A =(18 + 12) x 40 2 A = (30) x 40 2 A = 15 x 40 = 600 in 2 Agenda

Assessment 12 Agenda