I'm currently working on angles and bisectors and I was confused by the notes:
120degrees = x/2 + x/4 + x/8 + x/16
and multiply all that by sixteen to get:
120 * 16 = 15x
and then my teacher went from that to:
8 * 16 = x
can someone explain this to me? (from 120 * 16 = 15x to 8 * 16 = x)
thanks!
2007-09-05 11:38:33 · 3 answers · asked by d4rknes_rising 2 in Science & Mathematics ➔ Mathematics
more specifically i wanted to know why my teacher left the 16 alone.
shouldn't you divide both sides by 15?
so why did she leave the 16 alone?
2007-09-05 13:56:03 · update #1
I actually do not know why your teacher chose to express it as 8*16.
They divided both sides by 15. You can do this two ways, in my opinion.
1: Multiply out the left hand side (LHS) first. 120*16 = 1920. Then divide by 15, giving you x (128).
2: Leave the LHS alone and divide everything by 15. This gives you (16/15)*120. This will also give you x (128).
For some reason, your teacher has seemed to ignore the rule of dividing everything by 15 and just divided the 120 by 15, which gives you 8. Multipling out the LHS now, still gives 128, but it is (in my opinion, because it is how we were taught mathematics) not the correct process in which to do it.
I think that you should get into the habit of applying the division (or whatever it is the question requires) to the WHOLE eqaution and not just a select part.
2007-09-05 12:34:25 · answer #1 · answered by Hollie 1 · 0⤊ 0⤋
Your teacher divided 120 by 15 in his head and got 8.
So this made the next step x=8*16.
2007-09-05 18:44:37 · answer #2 · answered by ironduke8159 7 · 0⤊ 0⤋
You can divide both sides of an equation by any number or variable (in this case, 15) to simplify. 120 divided by 15 is 8, the 16 stays the same, and 15x divided by 15 is x.
2007-09-05 18:43:05 · answer #3 · answered by amshanker208 2 · 0⤊ 0⤋