Anyways, you know how there's like a plane of symmetry through the dimensions because of the identical faces opposite of each other? We talked about that for a bit. There's the pair of faces with height and length (hl). There's height and width (hw) and there's also length and width (lw).
(That's really hard to see but the first one shows height and length, the second shows height and width and the third shows length and width)
So that covers all the faces of the rectangular prism, right? Since there's 2 of each face, that makes the formula for the surface area of the rectangular prism:
We also got our tests back. Don't forget to get the parent signature.
After, we were asked to draw the net for a cylinder with a height of 6 and a circumference of 10 and cut it out without the circles on top which by the way is just a 6 by 10 rectangle since there are no circles. This is because the circumference is the length of the rectangle on the net (you know, if you unrolled the circle onto the length, it'd be the same).
So that was class. Here's the homework:
-Stick the nets in your journal and explain how to get the formula. I'm not sure if you're supposed to label them so can someone clarify that?
-Find the surface area of the cylinder with the height of 6 and circumference of 10
-How did you get the area of the circles on the top and bottom of the cylinder?
-Where is the symmetry on a cylinder and I think, how many planes of symmetry does a cylinder have?
-There's something on the grade 9 homepage to look at, I think.
I pick Zerlina for the next scribe.