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Where do Area Formulas Come From?. Important Terms: Base and Height. Base and height always make a right angle. The Rectangle: A Basic Shape. The Basic Grid: 12 units 2. A = bh. The Parallelogram. A = bh. The Triangle. A = ½ bh. The Trapezoid. Summary. Area of a rectangle = bh
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Important Terms: Base and Height • Base and height always make a right angle.
The Rectangle: A Basic Shape The Basic Grid: 12 units2 A = bh
The Parallelogram • A = bh
The Triangle • A = ½ bh
Summary • Area of a rectangle = bh • Area of a square = s2 • Area of a triangle = ½ bh • Area of a trapezoid = ½ h(base 1 + base 2)
Area of a Circle • A =πr2
Easy Way to Memorize Circle Formulas • C =πd • A =πr2 Circumference Formula Area Formula “Cherry pie’s delicious, apple pies are too”
What are the area formulas for these shapes? The Semicircle The Quarter-Circle