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Thursday, September 22, 2011

Surface Area

Quiz Answers (Review)

Area of rectangle: lh or lw

Area of circle: πr²
Area of triangle: bh/2
Area of square:
Circumference: πd or 2πr
Radius: d/2
Diameter: 2r or c/π
Perimeter of triangle: s + s + s
Perimeter of quadrilateral: s + s + s + s
Perimeter of any n-gon: Add all side lengths



a = bh

Trapezoid/Isosceles Trapezoid

a = ( b1 + b2/2 )h

Surface Area of nets


First way:
SA = 6s²
= 6(2²)
= 6(4)
= 24u²

Second way:
SA = 2(s²) + (Pob)h
= 2(2²) + 8(2)
= 2(4) + 16
= 8 + 16
= 24u²


First way:
SA = 2(s²) + 4(lw)
SA = 2(2²) + 4(3x2)
SA = 2(4) + 4(6)
SA = 8 + 24
SA = 32u²

Second way:
SA = 2(lw) + (Pob)h
SA = 2(3x2) + 10(2)
SA = 2(6) + 20
SA = 12 + 20
SA = 32u²

Identify 2 ways to find the surface area of this net.


  1. Hey Marie! Great job on this post. I liked how you found the pi symbol instead of writing it! Also the pictures and post was really neat. I liked how you gave 2 ways to find the surface area of the rectangle. Keep it up! :)

  2. Great Job Marie! I liked how you color codded the name of the formula from the formula. Also I liked the way you explained the Surface Area of the shape. Next time, maybe you should put the name of the Isosceles triangle closer to the picture.

  3. Nice job Marie! I like how you included pictures and made certain words stand out by either making them bold or adding colour. It was nice that as Thessa said, you included two different ways to get to the answer. However, I think you could have showed us how you did the homework we were given and explain to us how you did so. Just in case some of us don't understand the work. I also think maybe you could have shared a video or some links with us just so we could understand the topic more. But overall, I think you did a really good job. Keep it up :)

  4. Good job Marie! I liked the way your colors are meant to show the different sections of information clearly. I also liked how your pictures were clear and easy to understand. However you lack to show a video to help people in need. Also you can show what you would have done for some questions.

  5. Nice post Marie! You included all the notes we took that day and you even added what was homework which was good. All your pictures are drawn neatly and everything was spaced out well. To improve your blog, I think you could have added a video. Other than that, keep up the good work!

  6. Good job Marie! I like how you added pictures for each of the formulas. I also like how you made everything easy to read and understand. A way that you can improve on your post is to try and find a video so people can understand what your trying to say even more, but other than that good job!

  7. Good job Marie! I like how you used lots of colour to bold it from other words. Your post was very neat and everything was easy to see and read. I also like how you created a picture then showed the way to solve the problem. Keep it up! :)

  8. Great blog post Marie! It was very organized and easy to understand. I liked how you used the right amount of colors and your pictures were perfect. Though the formula for the area of the triangle is bh/2, not bb/2. Adding a link and/or video would have made your blog post a little better, but other than that, great job Marie.

  9. Great job Marie! I liked how your scribe was very neat, and well formed. I definitely liked how you used images to enhance your scribe even more, not only that, but it helped to explain it as well. You also highlighted the questions that were on the quiz, that helped a lot. Although, I think you should have added a link or two, or possibly even a video to add on to our learning. Other than that, you did a great job!

  10. Good job Marie! Your post was easy to look at. The pictures helped me imagine what i was looking at. I liked that you had all the formulas up there. Try adding in videos to gain a better understanding.

  11. Great job Marie. Your post was very clear and easy to understand. I liked how neat your pictures looked and showed the formulas and how to get the answer. Good job on showing both ways to find the answer. Also, good job putting up what was for hw! Next time add a video or a link to help us understand more. :) Keep it up!