00:00in this video we will look at a couple

00:03of examples to practice working with pie

00:05charts an example a it says the Red

00:09Cross Blood Donor clinic had a very

00:11successful morning collecting blood

00:13donations within three hours people have

00:16made donations and the following is a

00:17table showing the blood types of the

00:19donations and we have our table right

00:22here construct a pie chart to represent

00:25the data use a hundredths disc ok so in

00:30order to use a hundredths disc the first

00:32thing we need to know is the actual

00:34percentages this table tells us the

00:37numbers of people who donated blood type

00:40A blood type B blood type O and blood

00:43type a B but it doesn't tell us the

00:45percentage of people who donated blood

00:48type A etc so we have to first figure

00:52out those percentages so that we can

00:54make our pie chart so first figure out

00:57how many donations there were total so

01:00we're going to add up seven plus five

01:02plus nine plus four and what we get is

01:0725 donations total so now we can figure

01:12out the percentages for blood type a

01:15there were seven and seven out of 25 is

01:21twenty-eight percent or point twenty

01:24eight for blood type B there were five

01:28donations and five out of twenty five is

01:320.2 or twenty percent for blood type O

01:37there were nine donations out of 25

01:41which is thirty six percent and blood

01:46type a B there were four donations out

01:49of 25 which is sixteen percent now that

01:54we have our data in terms of percentages

01:56we can make our pie chart for blood type

01:59a we want to find twenty eight percent

02:02of our circle so these are broken into

02:06sections of ten percent so here would be

02:08ten percent twenty percent and we want

02:12Wandy 8% so all of this is blood type-a

02:18blood tabi is 20% so I'm going to take

02:23two whole sections of the circle and

02:27that will be my blood type B and don't

02:30forget to label or provide a key for

02:33your pie chart blood type O is 36% so we

02:38need to fill in three full sections plus

02:44six more little units and that's blood

02:51type O and finally blood type a B should

02:56be 16% so let's check we have 10 here

03:00plus 2 is 12 plus 4 is 16 so that's

03:03correct so we can fill in the last

03:07section is type a B and now you can

03:12visually see how all the different blood

03:17type donations compared now we're going

03:21to jump to example C a new restaurant is

03:24opening in town and the owner is trying

03:26very hard to complete the menu he wants

03:29to include a choice of five salads and

03:31it's presented his partner with the

03:33following pie chart to represent the

03:35results of a recent survey that he

03:36conducted of the townspeople the survey

03:39asks the question what is your favorite

03:41type kind of salad and we have our

03:44results here in a pie chart use the pie

03:48chart to answer the following questions

03:50one which salad was the most popular

03:53choice so if we want to know what's most

03:55popular that means which section of our

03:58pie takes up the biggest area and I can

04:01see that would be the Caesar salad 35%

04:04is the biggest of all the percentages so

04:08Caesar salad was the most popular the

04:14next question is which salad was the

04:17least popular choice so then we have to

04:19look for which of the salads has the

04:23and that would be the taco salad 10%

04:26that's the smallest number so the taco

04:29salad was the least popular choice and

04:33we have a couple more questions it's 300

04:37people were surveyed how many people

04:40chose each type of salad so remember

04:43that from the pie chart we don't know

04:45how many people were surveyed we only

04:47know the percentages so here it's

04:50telling us that there are 300 people so

04:52we have to go back and figure out okay

04:54well what's 35 percent of 300 people

04:57what's 25 percent of 300 people and so

05:00on so to figure that out you just are

05:02multiplying percentages so for the

05:05Caesar salad there were 300 people

05:07surveyed and 35 percent of those are

05:110.35 as the decimal preferred Caesar so

05:16multiply that out and you get 105 so 105

05:21people which is 35 percent of 300

05:26preferred Caesar salad for the chef's

05:29salad you're going to do 0.25 times 300

05:34and you get the result of 75 people for

05:41the garden salad you can do the same

05:42thing and do 300 times 0.1 3 and you got

05:5039 people for spinach you do 300 times

05:560.17 and you get 51 people and then

06:02finally for taco we need 300 times 0.1

06:0610% and we would get 30 all right

06:14the last question is what is the

06:16difference between the number of people

06:18who chose the spinach salad and the

06:20number of people who chose the garden

06:22salad so this question is about numbers

06:25of people as opposed to percentages so

06:28we're going to need to use the numbers

06:30of people that we found for the two

06:32salads spinach salad which was 51 and

06:3639 people for garden salad in order to

06:40answer this question if we hadn't

06:42already figured out the numbers of

06:43people you would need to do that first

06:45so the difference is 51 - 39 people

06:49which is 12 people so 12 more people

06:56preferred the spinach salad than the