20. Find the length of the diagonal of a square whose area is 128 cm Also, find its perimeter.
21. The area of a square field is 8 hectares. How long would a man take to cross it digonally waking with speed of 4kmph?
22. The cost of harvesting a square field at 900 per hectare is 8100. Find
the cost of putting a fence around it at rupee18
find its perimeter.
Answers
20. The area of a square is one side squared.
Let us consider:-
- A side is x cm.
The given area is 128 cm².
This implies that:-
cm ...(1)
Here, the diagonal of a square is always x × √2.
cm (ANSWER)
Here, the perimeter of a square is always 4x.
cm (ANSWER)
21. The area of a square is one side squared.
Let us consider:-
- A side is x m.
The given area is 80000 m².
This implies that:-
m
km ...(1)
Now
Here is the definition of speed.
(here, km/h)
As per the question:-
hours (ANSWER)
22. Given that:-
- (Cost):(Field)=1:9
- The cost of putting the fence is 18.
- The field is a square.
This results in insufficient information, because there is no area of field.
This problem cannot be solved. (ANSWER)
Extra Information
- Such problems with insufficient information, cannot be solved.
For example:-
"A captain owns 26 sheep and 10 goats. How old is the captain?"
- A physist does not memorize any formula. (Quora Answer)
For example, we used the definition.
Formulas are derived from definitions, they don't need to memorize but basics.
The derivation would look like this: