3 Simple Ways to Find the Area of a Pentagon
Introduction:
Finding the area of a pentagon, which is a five-sided polygon, might seem a bit tricky at first. However, with a few basic formulas and strategies, you can easily calculate the area of a pentagon just like any other shape. In this article, we will discuss three simple ways to find the area of a pentagon.
Method 1: Using the Apothem
1. Identify the apothem – The apothem is the distance from the center of a regular pentagon to the midpoint of one of its sides. If you know the apothem (a), then you can simply use the following formula to find the area:
Area = 5 x Side x Apothem / 2
2. If you don’t know the apothem but have side length (s) of the pentagon, you can calculate it using the Pythagorean theorem:
Apothem = Side / (2 × tan(π/5))
3. Now plug in your values for side length and apothem into the area formula to find your answer.
Method 2: Dividing into Triangles
1. Divide the pentagon into five congruent triangles by drawing lines from every corner point to the center of the shape.
2. Calculate base and height – In this method, we assume that all sides are equal in length (s). Since we’ve divided our pentagon into five triangles with equal base lengths, we can call all triangle’s height as h.
3. Determine one triangle’s area using 1/2 multiplied by base x height.
4. Multiply this resulting triangle’s area by five since there are five triangles in total to find your overall pentagonal area.
Method 3: Using Side Length and Diagonals
1. If you have only side lengths (s) and no other information, you can use the diagonals in a regular pentagon to help determine its area.
2. Find the length of one diagonal, which divides the pentagon into five isosceles triangles, with side length ratios of approximately 1:1:φ (φ: Golden ratio). You can calculate the length of the diagonal (d) using this formula:
Diagonal = Side × (1 + φ)
3. Now, you can use Heron’s formula to find the area of each of these triangles, and finally multiply by five for total pentagonal area.
In conclusion, calculating the area of a pentagon is easier than it looks. Choose a method that suits you best based on the given information. Once you have become comfortable with these techniques, you can find the area of a pentagon as effortlessly as any other shape!