$A$ hollow spherical shell is made of a metal of density $4.9 \, g/cm^3$. If its internal and external radii are $10 \, cm$ and $12 \, cm$ respectively,find the weight of the shell. (Take $\pi = 3.1416$) (in $gm$)

If the perimeter of an isosceles right triangle is $(6+3 \sqrt{2}) \text{ m}$,then the area of the triangle is ... $\text{m}^2$.

The angles of a quadrilateral are in the ratio of $2: 4: 7: 5$. The smallest angle of the quadrilateral is equal to the smallest angle of a triangle. One of the angles of the triangle is twice the smallest angle of the triangle. What is the second largest angle of the triangle? (in $^o$)

The inner circumference of a circular track is $440 \, cm$. The track is $14 \, cm$ wide. Find the diameter of the outer circle of the track? (in $cm$)

What is the area of a triangle whose sides are $9\, cm$,$12\, cm$,and $15\, cm$? (in $cm^2$)

The radius of the wheel of a vehicle is $70\, cm$. The wheel makes $10$ revolutions in $5\, seconds$. The speed of the vehicle is......$km/h$.