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Parallelograms have many interesting properties. You might be aware that these shapes are quadrilaterals with four different sides. But if we look a little closer at these shapes, we see that the diagonals of these shapes are particularly interesting. But what's so special about the diagonals of a parallelogram, and what can they teach us about math? Let's find out.
You might recall that when we talk about the diagonals of a parallelogram, we are talking about the lines that go from one corner to the opposite corner. Since a parallelogram has four corners, it also has two diagonals.
But here's the most important thing:
The diagonals bisect each other. While this might seem like a very simple observation, it can tell us some interesting things about the parallelogram. Let's take a closer look at the point at which the diagonals intersect.
This is the center of the parallelogram, and we can also call it the shape's "center of gravity". If we measure one diagonal line, then the point of intersection is the line's exact midpoint. This can help us make accurate observations and calculations in many situations.
If the diagonals bisect each other, then we know for sure that we're dealing with a parallelogram. But the opposite is also true: If we know that a quadrilateral is a parallelogram, we also know for sure that its diagonals must bisect each other.
Let's look at a picture of a parallelogram and its diagonals to make these rules easier to visualize:
Here are some fun facts about parallelograms:
As you might have guessed, there's a formula for finding the diagonal of a parallelogram. After all, mathematicians have created formulas for just about everything in the universe!
First, we should point out that the two diagonals in a parallelogram are not equal. We can say that one diagonal is p while the second diagonal is q.
We know that there are four angles in a parallelogram -- but the opposite angles are equal. So we can simplify things by working with just two angles, A and B.
We also know that a parallelogram has two sets of equal sides, so we can use just two values to represent their lengths, x and y.
With these values, we can create the following formulas:
You might remember that "cos" stands for "cosine." Cosine is a ratio, and we find this ratio by dividing the side adjacent to the angle by the long side.
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