math-percents, please!! Options

[KERP1UNK]

hey u guys i forgot how to do percent stuff..like this,...for example:

what number is 25% of 180??? or..

$5 is 4% of what amount??

i know i'm stupid...sorry! :P

[*stephinika*]

what number is 25% of 180??? or..

just take the percentage, divide it by 100.
so 25/100 = 0.25
multiply that by the number.
.25x180 = 45

$5 is 4% of what amount??

just use algebra.
$5/x = 4%
4% = 0.04
therefore:
5/x = 0.04
so you multiply the x across which gives you:
5 = 0.04x
so you then divide each side by 0.04 which gives you:
x = 125

hope that helps.

[yukichan]

try go:
25/100=x/180
and then cross multiply..then divide..

tip: whatever number that is after "of" goes on the bottom..whatever number that is before "is" goes on top..

[*xcaitlinx*]

i was taught to set up a proportion:

is = %
of 100

so, for Ex: "what number is 25% of 180?" you would do...

x = 25
180 100

cross multiply: 180x25 = 4,500
then divide by 100: 45

so, $45 is 25% of 180.

[*suddenly she*]

or convert the percentage to a decimal, then use the following rules.

"of" means to multiply.
"is" means to equal.

for example, what is 6% of 100?
what = .06 x 100.

i hope that helps.

[pingpang_0811]

1.)25% means 0.25
0.25 x 180... then you'll get the ans.

2.) let K be the amount.
5 = 4% K (as mentioned before.. all % can be divided into 100 into 0.xxx, we can calculate out that 4% = 0.04)
thus,
5 = 0.04K
5 divided into 0.04 = 0.04K divided into 0.04 (to eliminate the number)
then K = 125

[jue]

25% of 180

you would first change 25% to decimal form and that would be .25
then yu would just multiply 180 by .25 and after yu get that remember to move the two decimal places and yu get the answer.

and for $5 is 4% yu would just do the same thing as above^