Answer:
When we know all 3 sides, we use Heron's Formula
area = sqrt [s *(s-a) * (s-b) * (s-c)]
where "s" is the semi-perimeter which in this case equals
s = (6 + 8 + 12) / 2 = 13
area = sqrt [13 * 5 * 7 * 1]
area = sqrt 455
area = 21.3307290077
area = 21.33 square feet (rounded)
Step-by-step explanation:
The fourth class ends at 12:30 pm
<em><u>Solution:</u></em>
Given that Harold has 4 classes each morning
Each class is 1 hour long, and there are 10 minutes between classes
The first class is at 8 A.M
<em><u>To find: Time at which fourth class ends</u></em>
Since each is 1 hour long and 10 minutes gap between classes
First class = 8 A.M to 9 A.M
Second class = 9:10 A.M to 10 : 10 AM
Third class = 10 : 20 AM to 11 : 20 AM
Fourth class = 11 : 30 AM to 12 : 30 PM
Thus the fourth class ends at 12:30 pm
Answer:

Step-by-step explanation:
Since there are 20 students, this will be the denominator.
Now, to find how many students have a dog and a cat, you need to subtract all the numbers with 20. The leftover number will be the amount of students.
7+8+8=23
23-20=3
So, there are 3 students who have a dog and a cat.
So, the fraction will be 
Answer:
if you pit the shape in a straight line it would be 180 degrees now take 180 take 130 and 100 and subtract those add that to the other 30 then take 180 divided by 60
Answer:
She needs to sell 15 boxes of cookies to reach her goal