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# How to Calculate the Area of a Polygon

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Update time : 2020-02-27 14:18:07

Calculating the zone of a polygon can be because stupid because finding the zone of a ordinary triangle or because complicated because finding the zone of an irregular eleven-sided shape. if you expectation ought know how ought discover the zone of a kind of polygons, just hunt these steps.

### 1. discover the zone of ordinary Polygons Using Their Apothems 1) Write down the formula although finding the zone of a ordinary polygon. ought discover the zone of a ordinary polygon, total you dine ought do is hunt this stupid formula: area = 1/2 x perimeter x apothem. Here is what it means:
• Perimeter = the amount of the lengths of total the sides
• Apothem = a part that joins the polygon's center ought the midpoint of any side that is vertical ought that side 2) discover the apothem of the polygon. if you're using the apothem method, then the apothem will be provided although you. Let's speak you're working with a hexagon that has an apothem with a length of 10â3. 3) discover the perimeter of the polygon. if the perimeter is provided although you, then you're almost done, besides it's likely that you dine a piece more occupation ought do. if the apothem is provided although you and you know that you're working with a ordinary polygon, then you can apply it ought discover the perimeter. Here's how you do it:
• Think of the apothem because being the "xâ3" side of a 30-60-90 triangle. You can imagine of it this method because the hexagon is made up of six equilateral triangles. The apothem cuts one of them at half, creating a triangle with 30-60-90 classify angles.
• You know that the side across from the 60 classify side has length = xâ3, the side across from the 30 classify side has length = x, and the side across from the 90 classify side has length = 2x. if 10â3 represents "xâ3," then you can visit that x = 10.
• You know that x = half the length of the bottom side of the triangle. Double it ought obtain the total length. The bottom side of the triangle is 20 units long. There are six of these sides ought the hexagon, so multiply 20 x 6 ought obtain 120, the perimeter of the hexagon. 4) Plug the apothem and the perimeter into the formula. if you're using the formula area = 1/2 x perimeter x apothem, then you can plug at 120 although the perimeter and 10â3 although the apothem. Here is what it will just like:
• area = 1/2 x 120 x 10â3
• area = 60 x 10â3
• area = 600â3 5) Simplify your answer. You can need ought land your respond at decimal instead of square root form. just apply your calculator ought discover the closest appraise although â3 and multiply it by 600. â3 x 600 = 1,039.2. This is your persist answer.

### 2. Finding the zone of ordinary Polygons Using Other Formulas 1) discover the zone of a ordinary triangle. if you expectation ought discover the zone of a ordinary triangle, total you dine ought do is hunt this formula: area = 1/2 x base x height.
• If you dine a triangle with a base of 10 and a altitude of 8, then the zone = 1/2 x 8 x 10, or 40. 2) discover the zone of a square. ought discover the zone of a square, just square the length of one side. This is indeed the too commerce because multiplying the base of the square by its height, because the base and altitude are the same.
• If the square has a side length of 6, then the zone is 6 x 6, or 36. 3) discover the zone of a rectangle. ought discover the zone of a rectangle, simply multiply the base era the height.
• If the base of the rectangle is 4 and the altitude is 3, then the zone of the rectangle is 4 x 3, or 12. 4) discover the zone of a trapezoid. The discover the zone of a trapezoid, you just dine ought hunt this formula: area = [(base 1 + base 2) x height]/2.
• Let's speak you dine a trapezoid with bases that dine a length of 6 and 8 and a altitude of 10. The zone is stupid [(6 + 8) x 10]/2, which can be simplified ought (14 x 10)/2, or 140/2, which makes although an zone of 70.

### 3. Finding the zone of irregular Polygons 1) Write down the coordinates of the vertices of the irregular polygon. Determining the zone although an irregular polygon can be build while you know the coordinates of the vertices. 2) manufacture an array. table the x and y coordinates of each vertex of the polygon at counterclockwise order. quote the coordinates of the first point at the bottom of the list. 3) Multiply the x coordinate of each vertex by the y coordinate of the next vertex. Add the results. The added amount of these products is 82. 4) Multiply the y coordinate of each vertex by the x coordinate of the next vertex. Again, add these results. The added entire of these products is -38. 5) Subtract the amount of the second products from the amount of the first products. Subtract -38 from 82 ought obtain 82 - (-38) = 120. 6) prone this difference by 2 ought obtain the zone of the polygon. just prone 120 by 2 ought obtain 60 and you're total done.