Answer:
12+4/8
Step-by-step explanation:
sum means add and you need to divide 8 by whatever 12 and 4 equal
12+4= 16
16/8=2
2
AS we know that:

And we have the volume and we can calculate the SA,,,
So that, we can conclude:

Are you
satisfied?
Answer:
11.4
20/100 = x/57
Step-by-step explanation:
It is perhaps simplest just to translate the given English sentence into a mathematical sentence.
... 20% ... ... of ... 57 ... is ... what number
... 20/100 ... × ... 57 .... = ... what number . . . . . . . . translation to math sentence
... 11.4 = what number . . . . . . . . carry out the multiplication
_____
If you're asked to write this as a proportion, you can write it like this:

You can solve this proportion by multiplying by 57 (the denominator under "what number"). Doing so gives you the same arithmetic sentence as shown above.