How many balls of radius 4cm can be made from a solid sphere of lead of radius 8 cm?

1/tan Θ= .........

Two poles of heights 6 metres and 11 metres stand on a plane ground. If the distance between their feet is 12 metres then find the difference in the distance between their tops:

Find the sum of first 100 natural numbers:

If 3 men or 6 boys can do a piece of work in 20 days then how many days with 6men and 8 boys take to do the same work?

1.01x1.01x1.01-0.02x0.02x0.02/0.02x0.02+0.02x1.01+1.01x1.01= .....................