What is the radius of a circle,to the nearest $cm$,whose area is equal to the sum of the areas of the three circles of radii $22\, cm$,$19\, cm$,and $8\, cm$ respectively? (in $cm$)

If the radius of a circle is reduced by $40 \%$,then its circumference is reduced by (in $\%$).

The side of a square is $22 \, m$. What is the radius of the circle whose circumference is equal to the perimeter of the square? (in $m$)

The largest and the second largest angles of a triangle are in the ratio of $4:3$. The smallest angle is half the largest angle. What is the difference between the smallest and the largest angles of the triangle? (in $^o$)

The perimeter of a triangle is $30 \text{ cm}$ and its area is $30 \text{ cm}^2$. If the largest side measures $13 \text{ cm}$,then what is the length of the smallest side of the triangle? (in $\text{cm}$)

Find the area of a rhombus one of whose diagonals measures $10 \text{ cm}$ and the other $12 \text{ cm}$. (in $\text{cm}^2$)