The <u>correct answer</u> is:
Experiment
Explanation:
In an experiment, one group is given a treatment while at least one other group is not. After the treatment is finished, the results of the group that receive the treatment are compared with the results of the group (or groups) that do not receive the treatment, to determine if the treatment had any effect on the group.
In this problem, the different groups are the classes. Some classes use the new method, which is the treatment, while other classes do not. At the end of the year, the reading results of each class are compared to see if the treatment (new method) had any effect.
Answer:
length= 17.5 m , breadth = 12.5 m
Step-by-step explanation:
The ratio of length : breadth = 7 : 5 = 7x : 5x ( x is a multiplier )
Then
2l + 2b = perimeter ( l is length, b is breadth )
2(7x) + 2(5x) = 60
14x + 10x = 60
24x = 60 ( divide both sides by 24 )
x = 2.5
Then
length = 7x = 7 × 2.5 = 17.5 m
breadth = 5x = 5 × 2.5 = 12.5 m
V=(1/3)hpir^2
aprox
d=2r
d/2=r
d=24
r=24/2=12
V=2713
2713=(1/3)hpi(12^2)
2713=(1/3)hpi(144)
2713=48pih
divide both sides by 48
56.5208=hpi
aprox pi=3.14
divide both sides by 3.14
56.5208/3.14=h=18.0003
height=18cm
Step-by-step explanation:
(b) If 
then
Note that 
cancel out so we get
Solving for 
we get
(c) I'm not sure what the problem is asking for but here goes. As r doubles, 
becomes
