Presentation on theme: "BELL RINGER 5 m 11 m 1. Area = ? 7ft. P = 30 ft. A = ? 2."— Presentation transcript:
BELL RINGER 5 m 11 m 1. Area = ? 7ft. P = 30 ft. A = ? 2.
Area of a Triangle? 6m 10m 11m A B CD Area of Δ ABC? Area of Δ ADC?
AREA Brief review of finding the area of a triangle, rectangle, and parallelogram
Area of a Rectangle Read p.410, 411 Area is not a LENGTH, rather it is the number of SQUARE units worth of space that a shape takes up. A of rectangle = base * height Just like the bell ringer from today’s lesson.
Area of a Parallelogram The formula does not change! A=B*H 20 yds. 7 yds. 5 yds. A = 20 *5 = 100 yd 2 Why do you suppose this is? (Paste the triangle on the other side…)
Area of a Triangle A = Base * Height *1/2 Where does the ½ come from?? See example. Don’t forget, the ALTITUDE is the HEIGHT 4 cm 3 cm 2 ft 9 ft
What about a Trapezoid? b1 b2 h A = (b1 + b2) * h * 1/2 See example to understand why...