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Transparency 1. Click the mouse button or press the Space Bar to display the answers. Splash Screen. Example 1-4c. Objective. Find the areas of parallelograms, triangles, and trapezoids. Area of Parallelogram. Area of Triangle. Area of Trapezoid. Example 1-4c. Vocabulary. Base.
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Transparency 1 Click the mouse button or press the Space Bar to display the answers.
Example 1-4c Objective Find the areas of parallelograms, triangles, and trapezoids Area of Parallelogram Area of Triangle Area of Trapezoid
Example 1-4c Vocabulary Base Any side of the parallelogram
Example 1-4c Vocabulary Altitude A line segment perpendicular to the base with endpoints on the base and the side opposite the base
Lesson 1 Contents Example 1Find the Area of a Parallelogram Example 2Find the Area of a Triangle Example 3Find the Area of a Trapezoid
Example 1-1a Find the area of the parallelogram. The height is 2 centimeters The base is 7 centimeters Write formula for parallelogram Replace b with 7 cm A = 7 cm 2 cm Replace h with 2 cm cm2 A = 14 Multiply numbers Multiply units cm cm Answer: A = 14 cm2 1/3
Example 1-1b Find the area of the parallelogram. Answer: A = 18 in2 1/3
Example 1-2a Find the area of the triangle. The base is 22 inches. The height is 4 inches. Write formula for triangle (22 inches 4 inches) Replace b with 22 inches Replace h with 4 inches 2/3
Example 1-2b (22 inches 4 inches) Multiply numbers inches2 Multiply units Answer: A = 44 in2 2/3
Example 1-2c Find the area of the triangle. Answer: A = 30 in2 2/3
Example 1-3a Find the area of the trapezoid. The height is 3.4 yards. The lengths of the bases are 5 yards and 1 yard. Write formula for area of trapezoid (3.4 yards) (5 yards + 1 yard) Replace h with 3.4 yards 3/3
Example 1-3a Find the area of the trapezoid. The height is 3.4 yards. The lengths of the bases are 5 yards and 1 yard. Replace b1 with 5 yards (3.4 yards) (5 yards + 1 yard) Replace b2 with 1 yard 3/3
Example 1-3a Find the area of the trapezoid. Follow order of operations P E MD AS (3.4 yards) (5 yards + 1 yard) (3.4 yards) (6 yards) Work inside the parenthesis first (20.4) Multiply numbers Answer: Multiply units yard yard yards2 A = 10.2 3/3
Example 1-3b Find the area of the trapezoid. Answer: A = 20 in2 3/3
End of Lesson 1 Assignment
Example 1-4a PAINTINGA farmer plans to paint the triangular side of a large shed, shown below. Find the area to be painted. (Assume that no part of the window needs to be painted.) If a gallon of paint covers 350 square feet, how many gallons should the farmer buy? To find the area to be painted, subtract the area of the square from the area of the triangle. - s2 4/4
Example 1-4b Area of triangle Area of square or 387.5 387.5 - 9 = 378.5 The area to be painted is 378.5 feet2. 4/4
Example 1-4b The area to be painted is 378.5 feet2. If one gallon of paint covers 350 feet2 378.5 350 = 1.1 Since the farmer cannot buy a fraction of a gallon, he will need 2 gallons. Answer: 2 gallons 4/4
Answer: 1 qt Example 1-4c * PAINTINGTyler plans to paint his front door, shown at the right. Find the area to be painted. (Assume that no part of the windows will be painted.) If a quart of paint covers 50 square feet, how many quarts should Tyler buy? 4/4