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 
Hello,
very simple they intercept supplementary arcs. (making a sum of 360°/2 for inscribed angles )
Turn 7/10 into decimal. (0.7)
Keep adding by 0.7 until you get the number closest to 4.1
3.5 is the closest, if we add another 0.7, we get 4.2.
So, he can get 5 sections of 0.7m