Estimate the result by rounding the numbers to the second decimal before performing the operation. Then also round your answer to the second decimal. 8123÷0.211 How do you do it?

40615

Step-by-step explanation:

Note, rounding off decimals involves observing if the said decimal is up to the value of 5. If it is, then it can be rounded up, if not, its rounded off.

Since we need to round the numbers to the second decimal before performing the operation, we will have, 8123÷0.2

Note, 8123 has no decimal so we ignore

But 0.211 has a second decimal which is the first 1 so because it's not up to 5, we round it off to 0.

Hence we have 8123 ÷ 0.2= 40615.0

Since our answer has no decimal, we leave it like that.

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional