Answer:

Step-by-step explanation:
- this can be done by simple manipulation .
- in the given equation, A is the subject.
- so, by the above statement you can understand the meaning of making something as a subject.
- given equation: A = 1/2 bh
- multiply both the sides by 2,
2A = bh
- divide both the sides by h,

so, the required form is : 
Answer:
make sense next time
Step-by-step explanation:
For 10 miles, he takes = 85 min
then, 1 mile = 85/10 min.
Now, for 8 miles, it would be 85*8/10 = 68 minutes
The actual calculation for the circumference is 23.864 ft, so whichever answer is closest to that should be correct