12 cm / 4 m = 12 cm / 4 x 100 cm = 12/400 = 3/100.
Why do I have to times it by 100 out of all the numbers? How do I know what number to convert to like units so that the units divide out?
2006-07-13 19:21:53 · 5 answers · asked by mrxxbrian 2 in Education & Reference ➔ Homework Help
See.......u can divide two nubers only if they r in the same unit.
Lik in ur question both shud b either in m or in cms.
Now u know that 1m=100cm
So u can simplify it in 2 ways
1. converting m into cms
4m=4x100=400cms.
Now 12/400=3/100
2.converting cms into m
12 cm= 12/100m
So (12/100) / 4
= 12/400
=3/100
2006-07-13 19:29:19 · answer #1 · answered by nicegal 3 · 0⤊ 0⤋
you can have a ratio of two quantities only and only if they both are in the same units. so you cannot say the ratio of 20 dollars to 5 cents is 20/5=4.so either you convert the dollar into cents or the cents into dollars and find the ratio.here the thumb rule is convert the bigger unit into smaller units by multiplying and not convert the smaller units to bigger units by dividing because multiplication is easier than division.20 dollars=2000 cents.so the ratio is 2000/5=400
in your sum 12cm/4m meter is bigger than cm. so convert the 4m into cm by multiplying by 100 as 1m=100cm and the ratio becomes 12cm/400cm which on simplification gives3/100
since the units of the quantities are the same they get cancelled out leaving the ratio as a mere number without any units
2006-07-17 02:04:42 · answer #2 · answered by raj 7 · 0⤊ 0⤋
You have to multiply by 100 because there are 100 centimeters in every meter. Therefore, if you have 4 meters, you have 400 centimeters. You have to make sure you are working in the same units or you are going to get an error in your calculations. I assume you've been taught the metric ladder? Check out the link below for some basic practice.
2006-07-14 02:25:58 · answer #3 · answered by Niki 3 · 0⤊ 0⤋
You are not really muliplying by 100, you are multiplying by 1... which doesn't do anything except change units.
12 cm / 4m * 1m / 100cm = 12/400 = 2/100
1m / 100cm = 1, get it.
Also, if it helps, you can treat the units like variables.
2006-07-14 02:28:52 · answer #4 · answered by bogusman82 5 · 0⤊ 0⤋
because there are 100 cm in one meter and that is the basic unit of measurement.
king henry died by drinking chocolate milk.
K- kilo
H- Hecta
D- Deca
B- base unit (meter, liter...)
D- deci
C- centi
M- mili
you just move the decimal place over to where you want it. for example. with 4m into cm you move the decimal over to the right 2 times (centi) so you get 400. (same thing as multiplying by 100)
uhhhh hope this helps?
2006-07-14 02:29:15 · answer #5 · answered by tmbrian_008 1 · 0⤊ 0⤋