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Monday, October 3, 2011

Chelsea's Blog Post - Surface Area

Today in class, we solved 2 questions from the textbook (pg. 34- 35), in which both had to deal with finding out the surface area for them.

For the first question, we had to find the outside surface area of the chimney, which looked like this:

In order to find the surface area, first, we had to take the cylinders apart, as shown:

So, next, we had to find the radius:

Small rectangle:
r = d/2
r = 30/2
r = 15

Large rectangle:
r = d/2
r = 50/2
r = 25

After that, then we could complete the formula (remember, it said to give your answer to the nearest hundredth of a square metre):

The answer would now be 1.92m^2.

The second question we had to figure out, was finding the total area of the surfaces needed to be painted inside of a swimming pool, which looked like this:

Then, we had to take the shapes apart so that we could easily find the surface area:

Now, time to solve for the surface area (once again, to the nearest square metre):


- Questions #13, 15, and 16 in the textbook (pg. 34-35)
- Vocabulary Link
- Chapter One Reviews (both from the textbook and the homework book)

Try to do as many questions as you can! It's great practice for your Surface Area test on Wednesday! If you don't know what the test will be on, make sure you study:
  • square and rectangular based prisms
  • triangular based prism
  • cylinder
  • composite shapes (made up of 2 or more shapes)
If you don't understand any of the questions that you have attempted, be sure to ask Mr. Backe for help.

Also, if there is anything that I may have missed out in writing this post, please tell me and I'll fix it right away!

Now, the person who will do the next blog post is...

Yes, I chose you.

Don't forget to do your homework and study for Wednesday's test!


  1. Superb job, Chelsea. The pictures are a great way to utilize your tablet. The drawings are clear and extremely easy to understand. I think you should have added: mi ci di mlg deka haka and kilo. It would really help people understand how you converted your answer from cm^2 to m^2. I also think that you're supposed find the surface area of the ring, not the radius. But finding the radius is part of it. I also think that it would have been best if you added colour to important words.

  2. Good Job Chelsea! Your blog was very neat, and the pictures were great and exact. I agree with Anabelle that you should have added mi ci di m l g deka heka kilo and maybe explained how it worked, your explanation for how you answered the surface area for the shapes were neat and easy to undertsand, thank you for adding what was homework and good job for reminding everyone that their is a test on Wednesday. Good Job

  3. Amazing post Chelsea! I really like the pictures you made. They were easy to understand, and they were drawn very neatly. I also like how everything was well organized. I like how you used a bolder font for the answers, it made it stand out more. Next time, try to use a different coloured font for the key/important words. Thank you for including the homework, and what to study for the test on Wensday. Nice drawing at the bottem.

  4. Good Job Chelsea! The pictures help me to understand how to find the surface area of cylinders. Next time try to highlight or make important words presentable. Keep it up

  5. This was a really great post Chelsea ! The pictures that you made were really good. All the answers stood out which was good. You also explained how to find the surface area very well ! But maybe you could of added the mi ci di mlg deka haka and kilo notes that we wrote down.

  6. Great Job Chelsea! Really Good Job on your pictures. Your pictures are very neat and very easy to understand. I also agree with Patrick, next time you should add the mi ci di mlg deka haka and kilo notes. I like how you reminded everyone to study for the upcoming test on Wednesday! Keep it up!

  7. Great post! I enjoy looking at your pictures. It was organized too. Agreed with those two above. ^^ mi ci di mlg deka haka and kilo was notable.