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:
 
        
             
        
        
        
Answer: 91.2%
Step-by-step explanation:
Of the 1% of women that have breast cancer, 90% of those are tested positive with 8% of those being false positive. 8% of 90% is 8.8% so 91.2% chance. 
 
        
             
        
        
        
Answer: Always.
Step-by-step explanation:
The transitive property holds true for similar figures always because similar figures have similar shapes, the same angles and dimensions are proportional. 
For example:- If figure 1 is similar to figure 2 then both have same shape and same angles and dimensions are proportional .
If figure 2 is similar to figure 3 then both have same shape and same angles and dimensions are proportional .
⇒ figure 1 is similar to figure 3 the both have same shape and same angles and dimensions are proportional as the figure 2 .
Thus the transitive property holds true for similar figures always.