The common denominator is 40.
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 

V= 232 m (8x4x7.25) 232 is the volume
You have to find the square root of 169, then add the square root of 169 by 7
Hope this helped :)
Answer: 12.5 cm
Step-by-step explanation:
Equation would be:
1:80
?:1000
So you'll just have the cross multiply the equation above to find ? ( scale drawing lake). It'll be 1000*1/80 which will be 12.5 cm.