Answer:
The answer is False
Step-by-step explanation:
Answer: 
Step-by-step explanation:
Given
Cost of white-washing =Rs. 4989.60
Rate =20 per meter square
So, inside area of = 
The surface area of dome= 

The volume of air in the dome 

Option A is correct.
Step-by-step explanation:
We need to identify which statement is true in matrix addition.
In matrix addition we just add the corresponding elements.
In the options given only Option A is correct i.e, (n+4)-7 = 18
All other options have error in them.
In Option B there should be -12 instead of +12
In Option C there should be -11 instead of 11
In Option D we are not adding corresponding entries.
So, Option A is correct.
Keywords: Matrix addition
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So each 1 revolution it travels the distance around the rim of the wheele aka circumference
circumference=pi times diameter
diameter=21
circunference=pi times 21 or 21pi
so distance=number of revolutions times circunference
number of revolutions=3
subsitute
distance=3 times 21pi
distance=63pi
answer is 63pi
or aprox pi to 3.14 and do 63 times 3.14=197.82
aprox 197.82 inches