1. Area

2. Triangles and rectangles are examples of polygons. A polygon is a closed plane figure formed by three or more line segments. Each line segment forms a side of the polygon, and meets, but does not cross, another line segment at a common point. This common point is a vertex of a polygon.

3. Polygons are classified by the number of sides and angles they have.

4. A parallelogram has both pairs of opposite sides parallel and congruent. Both pairs of opposite angles are congruent.

5. A rectangle has four right angles. A rhombus has four congruent sides.

6. A square has four congruent sides and four right angles. A trapezoid has exactly one pair of parallel sides.

7. The area of a figure is the number of unit squares needed to cover the figure. Area is measured in square units.

8. Find the area of the rectangle. Course 2 4.5 in. 7.4 in. 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.

9. Find the area of the rectangle. Course 2 6.3 in. 8.2 in. A = lw A = 8.2 · 6.3 A = 51.66 The area of the rectangle is 51.66 in 2. Use the formula. Substitute for l and w. Multiply.

10. Find the area of the triangle. 5 8 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.

11. Find the area of the triangle. 9 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. 12

12. Find the area of the trapezoid. 5 in. 6 in. 9 in. 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.

13. Find the area of the trapezoid. A = 1212 h(b 1 + b 2 ) Use the formula. A = 1212 · 7(12 + 16) A = 1212 · 7(28) A = 98 The area of the trapezoid is 98 cm 2. Substitute. Multiply. Add. 12 cm 16 cm 7 cm