Take the root of both sides and solve.
if you have base ten blocks you can figure out the answer
61*40=60*40+1*40=2400+40=2440.
Therefore [] is 4
If te squre is inscribe in the cercle ten:The area of the circle is πR²
& the Area of te square is 2R², then the probability to land in the square :
2R²/πR²=2/π=0.6366 or 63.66%
General Idea:
The volume of cylinder is given by
, where r is the radius and h is the height of the cylinder.
Applying the concept:
Step 1: We need to find the volume of full cylinder with the given dimensions using the formula.
Volume of full cylinder 
Volume of half cylinder 
Step 2: Let x be the number of minutes of filling the sand.
of sand filled every 15 seconds, there are four 15 seconds in a minute.
So volume of sand filled in 1 minute
.
of sand taken out of cylindrical vase every minute.
Net volume of sand filled in 1 minute = Volume of sand filled in the vase in one minute - Volume of sand taken out in 1 minute
Net volume of sand filled in 1 minute
Volume of sand filled in x minutes
.
We need to set up an equation to find the number of minutes need to fill half the volume in cylindrical vase.

Conclusion:
The number of minutes required for the base be half filled with sand is 57