## Thursday, October 7, 2010

### Ezekiel's Scribe Post for October 7th, 2010

Today in math Mr. Backe showed us how to do our homework that we had to do.

Whole Shape
S.A. = 2(L) (W) + 2(L) (H) + 2(W) (H)
S.A. = 2(12) (5) + 2(12) (10) + 2(10) (5)
S.A. = 120+240+100
S.A. = 460 u ²
Hole Taken out
S.A. = 2(L) (W) + 2(L) (H) + 2(W) (H)
S.A .= 2(4) (5) + 2(4) (6) + 2(5) (6)
S.A. = 40+48+60
S.A. = 148 u ²
Faces Taken Out
S.A. = 2(LH)
S.A. = 2(4x6)
S.A. = 48
Total Surface Area
S.A. = 460+148-48
T.S.A. = 560 u ²
Mr. Backe asked us if we understood how to do surface area. Some of us didn't understand so he gave us another question. He told us we could do it on our own if we wanted. I did it on my own

Whole Shape
S.A. = 2(L) (W) + 2(L) (H) + 2(W) (H)
S.A. = 2(7) (8) + 2(7) (9) + 2(8) (9)
S.A. = 112+126+144
S.A. = 382 u ²
inside the hole
S.A. = 2(L) (W) + 2(L) (H) + 2(W) (H)
S.A. = 2(3) (8) + 2(3) (4) + 2(8) (4)
S.A. = 48+24+64
S.A. = 136 u ²
Faces Taken off
S.A. = 2(LH)
S.A. = 2(3 x 4)
S.A. = 24 u ²
Total Surface Area
S.A. = 382+136-24
T.S.A = 494 u ²

When everybody understood how to do the cube Mr.Backe showed asked us if we remembered how to find the circumference of a circle.
Circumference formula's: 2╥r or ╥d

Then he told us the formula for a cylinder
2╥rh+2╥r²
Then he gave us a cylinder that we were gonna do together.

r = d/2
r = 6/2
r = 3 cm
then he asked us to make a net of the cylinder

now we can solve the cylinders surface area
S.A. = 2╥rh+2╥r²
S.A. = 2╥(3) (12) + 2╥(3²)
S.A. = 229.19+56.55
S.A. = 282.74 cm²

I didn't put the first cylinder that we did together so.
r=d/2
r=10/2
r=5
S.A. = 2╥rh+2╥r²
S.A. = 2╥(5) (20)+2╥(5²)
S.A. = 628.32+157.08
S.A. = 785.4 cm ²
Remember for homework was in apply questions 13, 14, and 15 and Tutpup everyday

Also I pick Karra for the next scribe post. Have fun >:D

#### 1 comment:

1. GOod job! Nice explanation on what we did today. I liked how you showed picture of what we did that day. A lot of information about solving the cylinder, it helps me a lot. Maybe you should have put the important words in a different colour or bold it, so maybe it stands out. Uh..yeah, GOOD JOB.