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11.2 Areas of Triangles, Trapezoids, and Rhombi. 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. Area of a Triangle. h. b. Area of a Triangle. A= ½bh A= ½(8)(5) A= 20 cm. 5 cm. 2. 8 cm. Areas of Triangles.
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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. Area of a Triangle h b
Area of a Triangle A= ½bh A= ½(8)(5) A= 20 cm 5 cm 2 8 cm
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. Y H X Z G W
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. Areas of Triangles XZ= 39, HW=20, YG=21 Y 1 2 H X Z G W
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 ). Area of a Trapezoid b 1 1 h 2 1 2 b 2
Area of a Trapezoid A= ½h(b +b ) A= ½(8)(14+9) A= ½(8)(23) A= 4(23) A= 92 yd 1 2 14 yd 8 yd 2 9 yd
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) Area of a Rhombus 1 A B 2 1 2 D C
A= ½d d A= ½(30)(24) A= 380 in Area of a Rhombus 1 2 15 in 12 in 12 in 15 in 2
Finding Missing Measures Trapezoid PQRS has an area of 250 square inches. Find the height of PQRS. 20 in P Q S R 30 in
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. Finding Missing Measures 20 in Q P 1 2 S R 30 in
Assignment Page 606 #13-21,#22-34 Evens