8-2 Area of Polygons Warm Up Warm Up Lesson Presentation Lesson Presentation Problem of the Day Problem of the Day Lesson Quizzes Lesson Quizzes

8-2 Area of Polygons Warm Up Find each product    

8-2 Area of Polygons Problem of the Day How many 3 ft by 2 ft rectangles can you cut from one 8 ft by 4 ft rectangle? How much will be left over? 5 pieces; 2 ft 2 left over

8-2 Area of Polygons Prep for MA.7.G.2.1 Justify and use formulas for surface area and volume of pyramids, prisms, cylinders, and cones. Review of MA.6.G.4.3 Sunshine State Standards

8-2 Area of Polygons Vocabulary area

8-2 Area of Polygons The area of a figure is the number of unit squares needed to cover the figure. Area is measured in units of length squared, or square units.

8-2 Area of Polygons Find the area of the rectangle. Additional Example 1A: Finding the Area of Rectangles and Parallelograms A = lw A = 7.4 · 4.5 A = 33.3 The area of the rectangle is 33.3 in 2. Use the formula. Substitute for l and w. Multiply.

8-2 Area of Polygons Find the area of the parallelogram. A = bh A = 16 · 8 A = 128 The area of the parallelogram is 128 m 2. Additional Example 1B: Finding the Area of Rectangles and Parallelograms

8-2 Area of Polygons Find the area of the rectangle. 6.3 in. 8.2 in. A = lw A = 8.2 · 6.3 A = The area of the rectangle is in 2. Use the formula. Substitute for l and w. Multiply. Check It Out: Example 1A

8-2 Area of Polygons Find the area of the parallelogram. 6 cm 12 cm A = bh A = 12 · 6 A = 72 The area of the parallelogram is 72 cm 2. Check It Out: Example 1B

8-2 Area of Polygons

8-2 Area of Polygons Find the area of the triangle. Additional Example 2A: Finding the Area of a Triangle A = 1212 bh Use the formula. A = 1212 (8 · 5) Substitute 8 for b and 5 for h. A = 20 The area of the triangle is 20 square units.

8-2 Area of Polygons Find the area of the triangle. Additional Example 2B: Finding the Area of a Triangle A = 1212 bh Use the formula. A = 1212 (9 · 12) Substitute 9 for b and 12 for h. A = 54 The area of the triangle is 54 square units.

8-2 Area of Polygons Find the area of the triangle. A = 1212 bh Use the formula. A = 1212 (6 · 9) Substitute 6 for b and 9 for h. A = 27 The area of the triangle is 27 square units. Check It Out: Example 2A 6 9

8-2 Area of Polygons Find the area of the triangle. A = 1212 bh Use the formula. A = 1212 (7 · 10) Substitute 7 for b and 10 for h. A = 35 The area of the triangle is 35 square units. Check It Out: Example 2B 10 7

8-2 Area of Polygons The two parallel sides of a trapezoid are its bases, b 1 and b 2. The height of a trapezoid is the perpendicular distance between the bases.

8-2 Area of Polygons In the term b 1, the number 1 is called a subscript. It is read as “b-one” or “b sub-one.” Reading Math

8-2 Area of Polygons Find the area of the trapezoid. Additional Example 3A: Finding the Area of a Trapezoid A = 1212 h(b 1 + b 2 ) Use the formula. A = 1212 · 6(5 + 9) A = 1212 · 6(14) A = 42 The area of the trapezoid is 42 in 2. Substitute. Multiply. Add.

8-2 Area of Polygons Find the area of the trapezoid. Additional Example 3B: Finding the Area of a Trapezoid A = 1212 h(b 1 + b 2 ) Use the formula. A = 1212 · 7( ) A = 1212 · 7(28) A = 98 The area of the trapezoid is 98 cm 2. Substitute. Multiply. Add.

8-2 Area of Polygons Find the area of the trapezoid. A = 1212 h(b 1 + b 2 ) Use the formula. A = 1212 · 6(11 + 4) A = 1212 · 6(15) A = 45 The area of the trapezoid is 45 in 2. Substitute. Multiply. Add. Check It Out: Example 3A 4 in. 6 in. 11 in.

8-2 Area of Polygons Find the area of the trapezoid. A = 1212 h(b 1 + b 2 ) Use the formula. A = 1212 · 9(5 + 16) A = 1212 · 9(21) A = 94.5 The area of the trapezoid is 94.5 cm 2. Substitute. Multiply. Add. Check It Out: Example 3B 16 cm 5 cm 9 cm

8-2 Area of Polygons Standard Lesson Quiz Lesson Quizzes Lesson Quiz for Student Response Systems

8-2 Area of Polygons Lesson Quiz Find the area of each figure ft 2 45 ft ft or 9 in 2 60 ft ft 2

8-2 Area of Polygons 1. Identify the area of the rectangle. A cm 2 B cm 2 C cm 2 D. 81 cm 2 Lesson Quiz for Student Response Systems 9 cm 5.3 cm

8-2 Area of Polygons 2. Identify the area of the parallelogram. A. 144 in 2 B. 72 in 2 C. 50 in 2 D. 25 in 2 Lesson Quiz for Student Response Systems

8-2 Area of Polygons 3. Identify the area of the triangle. A. 48 cm 2 B. 20 cm 2 C. 36 cm 2 D. 96 cm 2 Lesson Quiz for Student Response Systems