Area - Area[]

In the Algebra View (at left), notice that the "value" of Polygon: poly1 is its area.

Click and leave your mouse on ABEArea1 to see the definition: Number ABEArea: Area[A,B,E] Click and leave your mouse on BCDEArea to see the definition: Number BCDEArea: Area[B,C,D,E] Click and leave your mouse on polygonArea to see the definition: Number polygonArea=ABEArea+BCDEArea

• Notice that polygonArea is the value of poly1.

In the Graphics View (at right), click and drag the vertices (points A, B, C, D and E) but keep the polygon simple (no crossings allowed!).

• If you want, define Area[A,B,C] and Area[C,D,E,A] and check that their sum is the area of poly1.