Rain, rain and more rain!!

Man, it has been raining cats and dogs lately! According to my Geography reference book, May-September is the period for Angin Monsun Barat Daya (AMBD), or in English, South-Western Monsoon Wind. It's really carrying a lot of rain to here in Selangor. The downside is, if there's no rain, it also blows the haze from Sumatera. But I think the haze has stopped, since it's not so hazy now.

Gosh, my gum is showing no sign of recovery. It still feels the same after about 1 week already. Tomorrow, I have a dentist appointment at 3.20pm. Whoa!! Nervous lah!! I think I might have Gingivitis!! Gingivitis is a gum disease. It happens when the bacteria from the plaque starts to deteriorate the gums. Well, it's something like that lah. I always taste dried blood whenever I lick that affected gum. Okay, okay, Julie's right, I'm overreacting!!

Anyway, my second trials are coming next week. I hope I won't forget my Sejarah. Currently, I'm studying Geography. I think I should start KH on Saturday, then Science on this Sunday. Hmm... Moral should take me about 1 day to finish. Well, it's just memorizing the moral values, nothing much.

Hey, wanna know some facts? If you have not heard of the following math facts, the you'll find this interesting. I know I did when I first heard of it.

Area of polygons

The picture above shows the way to calculate the area of a square and a rectangle. Everyone knows that.

Now, what about parallelograms?

Here's the trick: Do you see the triangle after the white, dotted line? Cut that out and move it to the other end of the parallelogram, and you should get the following:

And what do you get? A rectangle!! So, we can now conclude that the Area of a Parallelogram=Base x Height. This applies to Rhombuses as well. (or, Rhombi??) Rhombuses are slanted squares.

I guess a lot of people know about the paralellogram. So, I don't think you'll find that quite interesting. Now, how about triangles? Okay, triangles are quite different. Here's how to find the formula for the area of a triangle:

Right, you are given a triangle, something like what I drew above. I know, it's so pretty!! We all know, Area of a Triangle=1/2 x Base * Height. But how did that formula ever came to be? To find out, first, you duplicate that triangle. Take the triangle's clone, flip it over and place it so that one pair of corresponding sides are touching each other:
(The shaded triangle is the clone)
In the end, as you can see above, you'll get an awfully familiar shape. It's a parallelogram!!! And, as we've just discovered few minutes ago, Area of Parallelogram=Base x Height. So, the area of the figure above, A = Base x Height. Now, since Base x Height is for 2 triangles, 1 triangle will be equal to 1/2 x Base x Height!! Yay!!

Hmm... let's try something harder. Maybe a trapezium??
Alright then. A trapezium is a quadrilateral with only 1 pair of parallel sides. The formula to find its area is 1/2(a+b)h, where a+b is the sum of the parallel sides. Odd right? Why? It's simple to find out. Just do the same as what you can do to a triangle to find out it's area. Duplicate the trapezium, flip it over, place it at one end of the original trapezium. Let me bring out my trusty old friend, Paint!!


As you can see, when you do the cloning and flipping, you'll get a parallelogram!

Cool right? Well, that's all for today!!