1. 11.2 Areas of Triangles, Trapezoids, and Rhombi

2. Area of a Triangle If a triangle has an area of A square units, a base of b units, and a corresponding height of h units, then A= ½bh. b h

3. Area of a Triangle A= ½bh A= ½(8)(5) A= 20 cm 5 cm 8 cm 2

4. Areas of Triangles Find the area of quadrilateral XYZW if XZ= 39, HW= 20, and YG= 21. The area of the quadrilateral is equal to the sum of the areas of triangle XWZ and triangle XYZ. H G Y Z W X

5. Areas of Triangles Area of XYZW= area of triangle XYZ+ area of triangle XWZ A= ½bh + ½bh A= ½(39)(21) = ½(39)(20) A= 409.5 + 390 A= 799.5 The area of quadrilateral XYZW is 799.5 square units. H G Y Z W X 12 XZ= 39, HW=20, YG=21

6. Area of a Trapezoid If a trapezoid has an area of A square units, bases of b, units and b units, and a height of h units, then A= ½h(b +b ). 1 12 2 h b 1 b 2

7. Area of a Trapezoid A= ½h(b +b ) A= ½(8)(14+9) A= ½(8)(23) A= 4(23) A= 92 yd 14 yd 9 yd 8 yd 12 2

8. Area of a Rhombus If a rhombus has an area of A square unit and diagonals of d and d units, then A= ½d d. A= ½(AC)(BD) 1 2 12 AB C D

9. Area of a Rhombus A= ½d d A= ½(30)(24) A= 380 in 15 in 12 in 12 2

10. Finding Missing Measures Trapezoid PQRS has an area of 250 square inches. Find the height of PQRS. 30 in 20 in PQ RS

11. Finding Missing Measures Use the Formula for the area of a trapezoid and solve for h. A = ½h(b +b ) 250= ½h(20+30) 250= ½(50)h 250= 25h 10= h The height of the trapezoid PQRS is 10 inches. 12 20 in 30 in P Q RS

12. Assignment Page 606 #13-21,#22-34 Evens