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Contents Lesson 7-1Area of Parallelograms, Triangles, and Trapezoids Lesson 7-2Circumference and Area of Circles Lesson 7-3Area of Complex Figures Lesson 7-4Three-Dimensional Figures Lesson 7-5Volume of Prisms and Cylinders Lesson 7-6Volume of Pyramids and Cones Lesson 7-7Surface Area of Prisms and Cylinders Lesson 7-8Surface Area of Pyramids and Cones Lesson 7-9Precision and Significant Digits

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 4Use Area to Solve a Real-Life Problem

Example 1-1a Find the area of the parallelogram. The base is 7 centimeters. The height is 2 centimeters. Area of a parallelogram Replace b with 7 and h with 2. Multiply. Answer: The area is 14 square centimeters.

Example 1-1b Find the area of the parallelogram. Answer:

Example 1-2a Find the area of the triangle. The base is 22 inches. The height is 4 inches. Area of a triangle Replace b with 22 and h with 4.

Example 1-2b Multiply. Answer: The area is 44 square inches. Multiply.

Example 1-2c Find the area of the triangle. Answer:

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. Area of a trapezoid Replace h with 3.4, with 5, and with 1.

Example 1-3a Simplify. Answer: The area of the trapezoid is 10.2 square yards. or 10.2

Example 1-3b Find the area of the trapezoid. Answer:

Example 1-4a PAINTING A 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.

Example 1-4b Area of triangle Area of square or The area to be painted is – 9 or square feet. If one gallon of paint covers 350 square feet, then the farmer will need or about 1.1 gallons. Since the farmer cannot buy a fraction of a gallon, he will need 2 gallons. Answer: 2 gallons

Example 1-4c PAINTING Tyler 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? Answer: 1 qt

End of Lesson 1