Review: Area of 2-D Shapes Keystone Geometry

1. Review: Area of 2-D Shapes Keystone Geometry

2. b A = s² s h s 5 A = 6² = 36 sq. units 6 12 6 Squares and Rectangles Area of Rectangle: A = bh Area of Square: A = s² A = bh Example: Example: A = 12 x 5 = 60 sq. units

3. r Area of Circles Area of Circle: A =  r² 9 cm Example: A = (9)² = 81  sq. cm

4. b2 h h h b1 b b Triangles and Trapezoids h is the distance from a vertex of the triangle perpendicular to the opposite side. h is the distance from b1 to b2, perpendicular to each base

5. 12 8 7 6 6 Ex: Triangles and Trapezoids

6. 8 6 10 9 Parallelograms & Rhombi Area of Parallelogram: A = bh h b Example: Example: A = 9 x 6 = 54 sq. units A = ½ (8)(10) = 40 sq units

7. 8 10 4 14 8 12 Area of Regions The area of a region is the sum of all of its non-overlapping parts. A = ½(8)(10) A= 40 A = (12)(10) A= 120 A = (4)(8) A=32 A = (14)(8) A=112 Area = 40 + 120 + 32 + 112 = 304 sq. units

8. Areas of Regular Polygons If a regular polygon has an area of A square units, a perimeter of P units, and an apothem of a units, then A = ½ (a)(p). Perimeter = (6)(8) = 48 apothem = Area = ½ (48)( ) = sq. units 8