Hi guys, good day, it's me, Tijer MJ. Our topic for today class, it's all about regular and irregular polygons, and we're focusing on 5, 6, 8, or 10 sides. So without further ado, let's do this topic.
Now before we discuss with regular and irregular polygons, let's define first what is a polygon. Now a polygon is a closed figure made up of line segments, not curves, in a two-dimensional plane. So I have here given three illustration class, and you identify...
which of the following illustrations is a polygon? Now, if your answer is number three, that's correct, class. This is a polygon. Now, for number one, class, we cannot call this one a polygon because it has a curved side.
This particular side is a curved side. Therefore, this is not a polygon because a polygon is made up of line segments, not curves. Now, for number two, can we call this one a polygon?
Nope. We cannot call this one a polygon because it is an open figure. We don't have this particular side. So this is not a polygon. Now for number three, can we call this one a polygon?
Yeah. This is a polygon because it's made up of line segments and it is a closed figure. So if you have a closed figure made up of line segments, a two-dimensional plane, therefore this one is a polygon.
Now we call this one class a pentagon. A polygon with five sides, we call that one a pentagon. So one, two, three, four, five. Now if you understand the polygon class, let's talk about irregular and irregular polygons.
Irregular polygons, all sides are equal and all angles are of equal measure, while irregular polygons are polygons that do not have equal sides and equal angles. Now based on this given illustration class, what have you noticed? That's correct, on the first and second illustration, they have equal sides as well as they have equal angles.
Now in the third and fourth illustration, the sides are not equal and the angles are not equal. So once again, if they have equal sides and equal angles, we call this one regular polygons. I actually draw this one class using the protractor and the ruler so that they will have the same side as well as they will have the same angle.
So the next part of our video class is how to draw regular polygons using the protractor and the ruler. And we will explain that one class step by step. So feel free to see the video class. I will just put the link on the description down below.
So once again class, this one, we call this one regular pentagon because this side is equal to this side and this side is equal to this side. They have all equal sides and their angles are also equal. So this angle right here is congruent to this angle, to this angle, this angle, and this angle.
Five equal sides. Five equal angles, we call this one regular pentagon. So this one, hexagon, pentagon with six sides. Now we call this one regular hexagon if six sides are equal, six angles, six inter-angles are equal.
So once again, this side is congruent to this side, to this side. They have six congruent sides and six congruent angles. We call this one regular hexagon. Alright, now for this one class, we call this one a regular pentagon. It has five sides, we call this one pentagon, but it is a regular pentagon because this particular side is not equal as well as their angles.
So, based on the figure class, you can see that these angles are not equal as well as the sides. This side is shorter to this side, and this is the longest side, so they don't have the same cycles. So we call this one irregular pentagon. Same with this one, irregular hexagon. We have six sides, so one.
So let's count the number of sides. One, two, three, four, five, then six. Six sides.
And the sides are not equal as well as the angles. So we call this one irregular hexagon. So I hope you understand, class, with regards to regular polygons and irregular polygons. So let's have another example, class.
Eight and ten sides, so the octagon and the decagon. So let's have another example, class. class for the illustration. Now let's proceed now for the eight sides and ten sides.
Once again, class, a polygon with eight sides, we call this one octagon. A polygon with ten sides, we call it decagon. So I have here regular octagon. Once again, regular octagon, it has eight equal sides and eight equal interior angles. So if this is five centimeter for the sides, therefore, this is also five centimeter, five centimeter, five centimeter.
So this side is congruent to this side, this side, this side, this side, and this side, this side, this side. So eight congruent sides, eight equal sides. And for the angles, interior angles must be also congruent. So congruent. So this angle, alright, so this angle will be congruent to this angle.
So this angle will be congruent to this angle, to this angle. So 8 interior angles are congruent. Alright, and for this one, regular decagon, if this is 4 cm, this is also 4 cm, 4 cm, 4 cm.
All sides must be congruent for the regular decagon. So 10 sides are congruent. Of course, the interior angles is also congruent.
Alright, so this angle right here is also congruent. Now for this one class we have a regular octagon. It has eight sides.
So let's count the number of sides. So one, two, three, four, five, six, seven, then eight. So eight sides are not congruent as well as the angles they are not congruent.
So we call that irregular octagon. So we also have irregular decagon. So let's count the number of sides. So one, two, one, then two.
3, then 4, then 5, then 6, 7, 8, then 9, then 10. So 10 sides. 10 sides are not congruent as well as the interior angles. So we call that one irregular decagon.
So I hope you learned something new today class with regards to regular and irregular polygons. Do not forget to like, share, and subscribe. Be sure to share it to your friends and to your classmates so that we can help more students.
Once again, this is Teacher MJ. You have a great day, class. Goodbye for now.
Bye-bye.