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Dive into the world of trapezoids and quadrilaterals with this lesson. Learn how to find the area of a trapezoid using formulas and practical examples. Practice calculating areas to master your skills!
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Geometry Lessons Trapezoids Lesson
Quadrilateral … 4-sided shape Launch PARALLELOGRAM How would you find the AREA of this 4-sided shape? Area = base x height What kind of quadrilateral is shown here? h = 8 b = 12 Agenda
Quadrilateral … 4-sided shape Launch TRAPEZOID 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
Mini-Lesson The formula for the Area of a Trapezoid is… A = (b1+b2) x h 2 b2 height or h b1 Agenda
A = (b1+b2) x h 2 Let’s Test it out using the Trapezoids from the Explore… A = (8+4) x 2 2 A = (12) x 2 2 It works! A = 6 x 2 = 12 sq. units b2 = 4 Trapezoid A h = 2 b1 = 8 Agenda
A = (b1+b2) x h 2 Let’s try the formula again… A = (10+6) x 3 2 A = (16) x 3 2 Trapezoid B A = 8 x 3 A = 24 sq. units b2 = 6 h = 3 It works! b1 = 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! Agenda
Practice #1 A = (b1+b2) x h 2 A = (9+5) x 4 2 b2 = 5 A = (14) x 4 2 h = 4 A = 7 x 4 = 28 sq. units b1 = 9 Agenda
Practice #2 Now you try one… A = (b1+b2) x h 2 b2 = 3 A = (9+3) x 10 2 A = (12) x 10 2 h = 10 A = 6 x 10 = 60 sq. units b1 = 9 Agenda
Practice #3 Let’s try another one together, but make it a little more interesting! A = (b1+b2) x h 2 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. b2 = 4 ft A = (2+4) x 7 2 A = (6) x 7 2 h = 7 ft A = 3 x 7 = 21 ft2 b1 = 2 ft Agenda
Practice #4 Now you try another one… A = (b1+b2) x h 2 Brian is getting a custom sticker to completely cover the back of his guitar. How much space will it take up? A =(18+12) x 40 2 A = (30) x 40 2 b2 = 12 in A = 15 x 40 = 600 in2 h = 40 in Agenda b1 = 18 in
Assessment Agenda