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Published byNora Alexander Modified over 9 years ago
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8.1 Area of Rectangles and Parallelograms When you add to the truth you subtract from it. The Talmud
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Objectives Develop the concept of area Derive formulas for the areas of a: – Rectangle – Parallelogram – Triangles – Trapezoids – Kites Apply area formulas to solve problems
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1.Look at the parallelogram on your table. 2.Find the area of the figure in as many ways as possible. Activity
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We can use other shapes to help is find the area of a parallelogram. Rectangle Area Conjecture The area of a rectangle is given by the formula _____________ where A is the area, b is the length of the base, and h is the height of the rectangle. A = b * h
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Investigation: Area Formula for Parallelograms p. 412 Investigate! Parallelogram Area Conjecture: The area of a parallelogram is given by the formula ___________, where A is the area, b is the length of the base, and h is the height of the parallelogram. A = b* h
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8.2 Areas of Triangles, Trapezoids, and Kites Investigation 1: Area Formula for Triangles p.417 Investigation 2: Area Formula for Trapezoids p. 417 Investigation 3: Area Formula for Kites p. 418 Triangle Area Conjecture The area of a triangle is given by the formula _____________, where A is the area, b is the length of the base, and h is the height of the triangle. Trapezoid Area Conjecture The area of a trapezoid is given by the formula __________________, where A is the area, b 1 and b 2 are the lengths of the two bases, and h is the height of the trapezoid. Kite Area Conjecture The area of a kite is given by the formula ________________. A = ½ * b * h A = ½ * (b 1 + b 2 ) * h A = ½ * d 1 * d 2
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What some were are discoveries? Every triangle is half a parallelogram with the same base and height. Every trapezoid is half a parallelogram whose base is the sum of the bases of a trapezoid and whose height is the same as a trapezoid. Every kite is half a rectangle whose base and height are the kite’s diagonals.
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